drm/amdgpu/dc: fix DCN3.1 Makefile for PPC64

Port the necessary changes from previous DCN versions.
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn31/Makefile

@@ -13,12 +13,19 @@
 DCN31 = dcn31_resource.o dcn31_hubbub.o dcn31_hwseq.o dcn31_init.o dcn31_hubp.o \
 	dcn31_dccg.o dcn31_optc.o dcn31_dio_link_encoder.o dcn31_panel_cntl.o
 
-CFLAGS_$(AMDDALPATH)/dc/dcn31/dcn31_resource.o := -mhard-float -msse
+ifdef CONFIG_X86
+CFLAGS_$(AMDDALPATH)/dc/dcn31/dcn31_resource.o := -msse
+endif
+
+ifdef CONFIG_PPC64
+CFLAGS_$(AMDDALPATH)/dc/dcn31/dcn31_resource.o := -mhard-float -maltivec
+endif
 
 ifdef CONFIG_CC_IS_GCC
 ifeq ($(call cc-ifversion, -lt, 0701, y), y)
 IS_OLD_GCC = 1
 endif
+CFLAGS_$(AMDDALPATH)/dc/dcn31/dcn31_resource.o += -mhard-float
 endif
 
 ifdef IS_OLD_GCC