AGESA: Disable CAR with empty stack

Calling disable_cache_as_ram() with valuables in stack is not
a stable solution, as per documentation AMD_DISABLE_STACK
should destroy stack in cache.

Change-Id: I986bb7a88f53f7f7a0b05d4edcd5020f5dbeb4b7
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/18626
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/amd/agesa/s3_resume.c

@@ -51,7 +51,7 @@ static void move_stack_high_mem(void)
 #endif
 }
 
-static void set_resume_cache(void)
+void set_resume_cache(void)
 {
 	msr_t msr;