GFX-Display: Add support for HAD to be used as loadable module

GFX-Display: Add support for HAD to be used as loadable module

BZ: 23487

ospm_power_using_hw_begin/_end() APIs were not exported. Also, few
suspend/resume funcs only check for HAD as static module. Thus,
causing problems when HAD is used as a lodable module.

The solution is to add proper checks and export relevant APIs.

Change-Id: Ice8dd8a3da5b16ccef730b08ef85d0a7ce4c5bde
Signed-off-by: Shreyas Neerebailoor <shreyasx.neerebailoor@intel.com>
Signed-off-by: Tong, Bo <box.tong@intel.com>
Reviewed-on: http://android.intel.com:8080/35122
Reviewed-by: Agarwal, Vaibhav <vaibhav.agarwal@intel.com>
Reviewed-by: Abdullah, Omair M <omair.m.abdullah@intel.com>
Reviewed-by: Xu, Randy <randy.xu@intel.com>
Reviewed-by: Kuppuswamy, Sathyanarayanan <sathyanarayanan.kuppuswamy@intel.com>
Reviewed-by: Gupta, ArvindX K <arvindx.k.gupta@intel.com>
Reviewed-by: Gross, Mark <mark.gross@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>