ibm: Remove the openbmc-witherspoon distro

The meta-ibm layer supported two different DISTROs depending on the
machine being built. This caused complexity since the user needed to
remember to specify the DISTRO name, in addition to the CI build scripts
needed to check for the machine name being built to override the default
DISTRO.

For simplification, remove the openbmc-witherspoon DISTRO, which is the
openpower DISTRO plus additional features, and move these features to
the machine configuration files. Make the openpower DISTRO the default.

Tested: Built witherspoon and p10bmc using "source setup <machine> build"
        followed by "bitbake obmc-phosphor-image" without specifying the
        DISTRO. Verified witherspoon built a ubi image and p10bmc built
        a emmc image.

Change-Id: If33441ab4ad2dc0fbedde09f0db91d691d2da4f7
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-ibm/conf/local.conf.sample b/meta-ibm/conf/local.conf.sample
index 9f2228b..2ee8833 100644
--- a/meta-ibm/conf/local.conf.sample
+++ b/meta-ibm/conf/local.conf.sample
@@ -2,7 +2,7 @@
 #MACHINE ?= "p10bmc"
 #MACHINE ?= "swift"
 MACHINE ??= "witherspoon"
-DISTRO ?= "openbmc-witherspoon"
+DISTRO ?= "openbmc-openpower"
 PACKAGE_CLASSES ?= "package_rpm"
 SANITY_TESTED_DISTROS_append ?= " *"
 EXTRA_IMAGE_FEATURES = "debug-tweaks"