[PATCH] drm/amd: Guard IS_OLD_GCC assignment with CONFIG_CC_IS_GCC

[Nathan Chancellor <nathan@kernel.org>]

cc-ifversion only works for GCC, as clang pretends to be GCC 4.2.1 for
glibc compatibility, which means IS_OLD_GCC will get set and unsupported
flags will be passed to clang when building certain code within the DCN
files:

clang-14: error: unknown argument: '-mpreferred-stack-boundary=4'
make[5]: *** [scripts/Makefile.build:277: drivers/gpu/drm/amd/amdgpu/../display/dc/dcn201/dcn201_resource.o] Error 1

Guard the call to cc-ifversion with CONFIG_CC_IS_GCC so that everything
continues to work properly. See commit 00db297106e8 ("drm/amdgpu: fix stack
alignment ABI mismatch for GCC 7.1+") for more context.

Fixes: ff7e396f822f ("drm/amd/display: add cyan_skillfish display support")
Link: https://github.com/ClangBuiltLinux/linux/issues/1468
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dcn201/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn201/Makefile b/drivers/gpu/drm/amd/display/dc/dcn201/Makefile
index d98d69705117..96cbd4ccd344 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn201/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dcn201/Makefile
@@ -14,9 +14,11 @@ ifdef CONFIG_PPC64
 CFLAGS_$(AMDDALPATH)/dc/dcn201/dcn201_resource.o := -mhard-float -maltivec
 endif
 
+ifdef CONFIG_CC_IS_GCC
 ifeq ($(call cc-ifversion, -lt, 0701, y), y)
 IS_OLD_GCC = 1
 endif
+endif
 
 ifdef CONFIG_X86
 ifdef IS_OLD_GCC

base-commit: b47b99e30cca8906753c83205e8c6179045dd725
-- 
2.33.0.591.gddb1055343