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/chromebook_link_defconfig b/configs/chromebook_link_defconfig
index 21e85f3..fbecf8b 100644
--- a/configs/chromebook_link_defconfig
+++ b/configs/chromebook_link_defconfig
@@ -4,6 +4,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="chromebook_link"
 CONFIG_TARGET_CHROMEBOOK_LINK=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