uboot: build with -O2 on all architectures

The -Os option was disabled due to a bug in gcc building bad binaries for ARM
in an earlier commit:

f2dc7fadd8

This caused problems for powerpc which was resolved by replacing -Os with
-O2 for that architecture:

d0eb6794d9

Using -O2 also works for ARM, so there is no need to condition using -O2 on
powerpc. Remove the condition and use -O2 on all architectures.

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Ilya Yanok <yanok@emcraft.com>
CC: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-bsp/uboot/u-boot.inc

@@ -12,7 +12,7 @@ inherit deploy
 PARALLEL_MAKE=""
 
 # GCC 4.5.1 builds unusable binaries using -Os, remove it from OPTFLAGS
-EXTRA_OEMAKE = "CROSS_COMPILE=${TARGET_PREFIX} OPTFLAGS=''"
+EXTRA_OEMAKE = "CROSS_COMPILE=${TARGET_PREFIX} OPTFLAGS='-O2'"
 
 UBOOT_MACHINE ?= "${MACHINE}_config"
 UBOOT_IMAGE ?= "u-boot-${MACHINE}-${PV}-${PR}.bin"
@@ -23,12 +23,7 @@ do_compile () {
 	unset CFLAGS
 	unset CPPFLAGS
 	oe_runmake ${UBOOT_MACHINE}
-	# -Os is disabled on PowerPC
-	if [ ${TARGET_ARCH} == "powerpc" ] ; then
-		oe_runmake OPTFLAGS=-O2 all
-	else
-		oe_runmake all
-	fi
+	oe_runmake all
 }
 
 do_deploy () {