amdfam10: Clean leftover prototypes

Change-Id: Ic3278cb1148c34284aba59f6f588713b683ca90b
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37235
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Michał Żygowski <michal.zygowski@3mdeb.com>

src/include/cpu/amd/car.h

@@ -4,10 +4,6 @@
 #include <arch/cpu.h>
 
 void cache_as_ram_main(unsigned long bist, unsigned long cpu_init_detectedx);
-asmlinkage void *post_cache_as_ram(void);
-asmlinkage void cache_as_ram_new_stack(void);
-
-void disable_cache_as_ram(void);
 
 void asmlinkage early_all_cores(void);