usb: add usb host mode support for Cloverview

usb: add usb host mode support for Cloverview

BZ: 19640

This patch enables usb host mode for Cloverview. Note that SRAM usage is disabled
for host mode because enabling SRAM from the driver will make usb transfer
unstable. For details, see Cloverview sighting #4375244 and #4375558.

Change-Id: Icc9995c4730b2fc0f3ccbb25a94bdc660cd67548
Signed-off-by: Bin Gao <bin.gao@intel.com>
Reviewed-on: http://android.intel.com:8080/31443
Reviewed-by: Yang, Fei <fei.yang@intel.com>
Reviewed-by: Wu, Hao <hao.wu@intel.com>
Reviewed-by: Gross, Mark <mark.gross@intel.com>
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>