[Skiboot] [PATCH] external: Fix cross compilation issue

[Vasant Hegde]

For some reason Makefile thinks compiler variables like CC is already
assigned and ignores CROSS_COMPILE flags. Hence I'm not able to generate
arm binary on x86.

Use default assignment operator instead of conditional assignment
operator (?=) in Makefile.

Fixes: 3137d249 (pflash: Allow building under yocto.)
CC: Patrick Williams <patrick at stwcx.xyz>
CC: Stewart Smith <stewart at linux.vnet.ibm.com>
Signed-off-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
---
 external/common/rules.mk | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/external/common/rules.mk b/external/common/rules.mk
index bb12fd5..416a40d 100644
--- a/external/common/rules.mk
+++ b/external/common/rules.mk
@@ -1,5 +1,5 @@
-CC ?= $(CROSS_COMPILE)gcc
-LD ?= $(CROSS_COMPILE)ld
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)ld
 ARCH := $(shell $(GET_ARCH) "$(CROSS_COMPILE)")
 
 ifeq ($(ARCH),ARCH_ARM)
-- 
2.5.5