xcompile: Only include arm64 erratum check in arm64 section

Clean up the output file a bit by only including the erratum
for arm64 into the that architecture section instead of
every architecture.

Change-Id: Ib6276f12aee5deb92a03e1c4fa2ad57db46bdc8f
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12842
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

util/xcompile/xcompile

@@ -227,9 +227,19 @@ endif
 CPP_${TARCH}:=${GCCPREFIX}cpp
 AS_${TARCH}:=${GCCPREFIX}as ${ASFLAGS}
 LD_${TARCH}:=${GCCPREFIX}ld${LINKER_SUFFIX} ${LDFLAGS}
+EOF
+
+	if [ "${TARCH}" = "arm64" ]; then
+	cat <<EOF
+
 ifeq (\$(CONFIG_ARM64_A53_ERRATUM_843419)\$(CONFIG_LP_ARM64_A53_ERRATUM_843419),y)
 	LD_${TARCH}+=${LDFLAGS_ARM64_A53_ERRATUM_843419}
 endif
+
+EOF
+	fi # if [ "${TARCH}" = "arm64" ]
+
+	cat <<EOF
 NM_${TARCH}:=${GCCPREFIX}nm
 OBJCOPY_${TARCH}:=${GCCPREFIX}objcopy
 OBJDUMP_${TARCH}:=${GCCPREFIX}objdump