AMD: Set the mask of MTRR according to CONFIG_CPU_ADDR_BITS

The high bits of mtrr mask are MBZ (Must be zero). Writing 1 to these
bits will cause exception. So be carefull when spread this change.

The supermicro/h8scm needs more work. Currently it is set as it was.
We need to check if the F10 and F15 have different value.

Change-Id: I2dd8bf07ecee2fe4d1721cec6b21623556e68947
Signed-off-by: Zheng Bao <zheng.bao@amd.com>
Signed-off-by: zbao <fishbaozi@gmail.com>
Reviewed-on: http://review.coreboot.org/1661
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>
diff --git a/src/mainboard/supermicro/h8scm/Kconfig b/src/mainboard/supermicro/h8scm/Kconfig
index e7dae66..b93bfad 100644
--- a/src/mainboard/supermicro/h8scm/Kconfig
+++ b/src/mainboard/supermicro/h8scm/Kconfig
@@ -59,6 +59,10 @@
 	int
 	default 16
 
+config CPU_ADDR_BITS
+	int
+	default 36  # TODO: Set it conservatively to match both fam10 & 15
+
 config HW_MEM_HOLE_SIZE_AUTO_INC
 	bool
 	default n