cpu/x86/mtrr: move cache_ramstage() to its only user

The Intel i3100 northbridge code is the only user of
cache_ramstage(). Therefore, place it next to the sole
consumer.

Change-Id: If15fb8d84f98dce7f4de9e089ec33035622d8f74
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/14097
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/cpu/x86/mtrr/earlymtrr.c

@@ -20,14 +20,6 @@ void set_var_mtrr(
 }
 
 #if !IS_ENABLED(CONFIG_CACHE_AS_RAM)
-static void cache_ramstage(void)
-{
-	/* Enable caching for lower 1MB and ram stage using variable mtrr */
-	disable_cache();
-	set_var_mtrr(0, 0x00000000, CONFIG_RAMTOP, MTRR_TYPE_WRBACK);
-	enable_cache();
-}
-
 const int addr_det = 0;
 
 /* the fixed and variable MTRRs are power-up with random values,