Enable Merrifield storage support on ICS mainline

Enable Merrifield storage support on ICS mainline

BZ: 27386

Add PCI device ID for Merrifield mmc host controllers
so that they can be recognized by kernel and thus enable
the eMMC/SD/SDIO support for Merrifield platform.

Please note, on Merrifield, all the 4 eMMC/SD/SDIO
host controllers share single PCI device ID but have
different Function number. This is different from
Medfield and Moorestown.

Change-Id: I0da7f0ce7ec77bcf5c8bdbed1a58bccb192ce145
Signed-off-by: Yunpeng Gao <yunpeng.gao@intel.com>
Reviewed-on: http://android.intel.com:8080/40284
Reviewed-by: Tang, Richard <richard.tang@intel.com>
Tested-by: Sun, Jianhua <jianhua.sun@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>