skiboot: Remove PREFIX patch

There's no need to patch skiboot, we can just use the existing 'prefix'
variable.

Change-Id: I65c00333c86cf1d42aa03760c1317fa479b74a20
Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/meta-openbmc-machines/meta-openpower/common/recipes-bsp/skiboot/skiboot.inc b/meta-openbmc-machines/meta-openpower/common/recipes-bsp/skiboot/skiboot.inc
index 1356479..9a2b1e5 100644
--- a/meta-openbmc-machines/meta-openpower/common/recipes-bsp/skiboot/skiboot.inc
+++ b/meta-openbmc-machines/meta-openpower/common/recipes-bsp/skiboot/skiboot.inc
@@ -2,7 +2,6 @@
 LICENSE = "Apache-2.0"
 
 SRC_URI += "git://github.com/open-power/skiboot.git;nobranch=1"
-SRC_URI += "file://0001-external-Use-more-standard-PREFIX-vs-prefix.patch"
 
 FILESEXTRAPATHS_append := "${THISDIR}/skiboot:"
 
@@ -21,6 +20,8 @@
     oe_runmake -C ${SKIBOOT_SUBDIR} all
 }
 
+# TODO: remove PREFIX=$prefix when updating to a version that has
+# http://patchwork.ozlabs.org/patch/923741/ is merged upstream
 do_install() {
-    oe_runmake -C ${SKIBOOT_SUBDIR} install DESTDIR=${D} PREFIX=/usr
+    oe_runmake -C ${SKIBOOT_SUBDIR} install DESTDIR=${D} prefix=/usr PREFIX=$prefix
 }