x86: Move mrccache.[c|h] to a common place

mrccache implementation can be common for all boards. Move it
from ivybridge cpu directory to the common lib directory.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/chromebox_panther_defconfig b/configs/chromebox_panther_defconfig
index 70a22a9..663aab0 100644
--- a/configs/chromebox_panther_defconfig
+++ b/configs/chromebox_panther_defconfig
@@ -3,6 +3,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="chromebox_panther"
 CONFIG_TARGET_CHROMEBOX_PANTHER=y
 CONFIG_HAVE_MRC=y
+CONFIG_ENABLE_MRC_CACHE=y
 CONFIG_HAVE_VGA_BIOS=y
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_FLASH is not set