Drop Kconfig VAR_MTRR_HOLE option

All but one board use the default value of enabled. Disabling
this can only increase the number of MTRR registers used.

Change-Id: I7d28adc31b9fae2301e4ff78fcb96486f81d5ec2
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/1213
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/cpu/Kconfig

@@ -61,11 +61,4 @@ config SSE2
 	  streaming SIMD instructions. Some parts of coreboot can be built
 	  with more efficient code if SSE2 instructions are available.
 
-config VAR_MTRR_HOLE
-	bool
-	default y
-	help
-		Unset this if you don't want the MTRR code to use
-		subtractive MTRRs
-
 endif # ARCH_X86