build-setup: remove duplicate machine config

The earlier scripts are now using 'setup' directly to
get machine configuration information.  Remove a bunch
of duplicate / unnecessary configuration such as the
template directory (which is determined automatically
by setup) and DISTRO (which is often represented in
local.conf.sample).  Leave just the configs where we
deviate from the default in openbmc/openbmc.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If00f8d3ba5a16a0d163c321692048b37cd913dd3
diff --git a/build-setup.sh b/build-setup.sh
index 234fd10..1ecf999 100755
--- a/build-setup.sh
+++ b/build-setup.sh
@@ -38,10 +38,8 @@
 #                     ubuntu: latest|16.04|14.04|trusty|xenial
 #                     fedora: 23|24|25
 #                     Default: "latest"
-#  target             The target we aim to build:
-#                     evb-ast2500|palmetto|qemu|qemux86-64
-#                     romulus|s2600wf|witherspoon|zaius|tiogapass|gsj|mihawk
-#                     witherspoon-tacoma|rainier
+#  target             The target we aim to build.  Any system supported by
+#                     the openbmc/openbmc `setup` script is an option.
 #                     Default: "qemuarm"
 #  no_tar             Set to true if you do not want the debug tar built
 #                     Default: "false"
@@ -144,79 +142,25 @@
 fi
 chown "${UID}:${GROUPS[0]}" "${xtrct_path}"
 
-# Work out what build target we should be running and set BitBake command
-MACHINE=""
+# Perform overrides for specific machines as required.
 case ${target} in
-  palmetto)
-    LAYER_DIR="meta-ibm/meta-palmetto"
-    MACHINE="palmetto"
-    DISTRO="openbmc-openpower"
-    ;;
-  swift)
-    LAYER_DIR="meta-ibm"
-    MACHINE="swift"
-    DISTRO="openbmc-witherspoon"
-    ;;
-  mihawk)
-    LAYER_DIR="meta-ibm"
-    MACHINE="mihawk"
-    DISTRO="openbmc-witherspoon"
-    ;;
-  witherspoon)
-    LAYER_DIR="meta-ibm"
-    MACHINE="witherspoon"
-    DISTRO="openbmc-witherspoon"
-    ;;
-  witherspoon-128)
-    LAYER_DIR="meta-ibm"
-    MACHINE="witherspoon-128"
-    DISTRO="openbmc-witherspoon"
-    ;;
   witherspoon-tacoma)
-    LAYER_DIR="meta-ibm"
-    MACHINE="witherspoon-tacoma"
     DISTRO="openbmc-openpower"
     ;;
   rainier)
-    LAYER_DIR="meta-ibm"
-    MACHINE="rainier"
     DISTRO="openbmc-openpower"
     ;;
-  evb-ast2500)
-    LAYER_DIR="meta-evb/meta-evb-aspeed/meta-evb-ast2500"
-    MACHINE="evb-ast2500"
-    DISTRO="openbmc-phosphor"
-    ;;
-  s2600wf)
-    LAYER_DIR="meta-intel/meta-s2600wf"
-    MACHINE="s2600wf"
-    DISTRO="openbmc-phosphor"
-    ;;
   zaius)
-    LAYER_DIR="meta-ingrasys/meta-zaius"
-    MACHINE="zaius"
+    # This should probably be openbmc-zaius, which is default.
     DISTRO="openbmc-openpower"
     ;;
-  romulus)
-    LAYER_DIR="meta-ibm/meta-romulus"
-    MACHINE="romulus"
-    DISTRO="openbmc-openpower"
-    ;;
-  tiogapass)
-    LAYER_DIR="meta-facebook/meta-tiogapass"
-    MACHINE="tiogapass"
-    DISTRO="openbmc-phosphor"
-    ;;
-  gsj)
-    LAYER_DIR="meta-quanta/meta-gsj"
-    MACHINE="gsj"
-    # Use default DISTRO from layer
-    ;;
   *)
-    exit 1
+    echo "Unspecified machine ${target}; default to local.sample.conf values."
     ;;
 esac
 
+# Set build target and BitBake command
+MACHINE="${target}"
 BITBAKE_CMD="source ./setup ${MACHINE} ${build_dir}"
 
 # Configure Docker build