soc/amd/common: Make the function in cpu.c available in romstage

Change-Id: I909f74853a37a783582471e05071bc3d07e3dcf8
Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61310
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/soc/amd/common/block/cpu/noncar/Makefile.inc

@@ -5,6 +5,7 @@ bootblock-y += pre_c.S
 bootblock-y += write_resume_eip.c
 romstage-y += memmap.c
 ramstage-y += cpu.c
+romstage-y += cpu.c
 ramstage-y += memmap.c
 
 endif # CONFIG_SOC_AMD_COMMON_BLOCK_NONCAR