Restructured mrst.c

Restructured mrst.c

BZ: 22780

Mrst.c file contents are divided into soc & board components. Details are,
Platform/intel-mid.c - Common SOC functionalities are part of this file.
		       Like SFI parsing, platform device initialization
		       routines,etc.
Platform/mrst/mrst.c - Moorestown specific code should go into this file.
Platform/mfld/mfld.c - Medfield specific code should go into this file.
Platform/mfld/board-blackbay.c - Board specific initilizations should be part
				 of this file.

Added a new member(device_handler) to devs_id structure. Platform devices
can use this member to define their own device handlers. If the value is
left NULL then default handler will get called.

intel_mid_weak_decls.h contains weak declaration of the functions defined in
intel-mid.c.It will help us to override these functions in SOC specific files.

Change-Id: I7340a5a197af6340b899e8dff0f1a9ca0929fe2b
Signed-off-by: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@intel.com>
Reviewed-on: http://android.intel.com:8080/34375
Reviewed-by: Yang, Fei <fei.yang@intel.com>
Tested-by: Yang, Fei <fei.yang@intel.com>
Reviewed-by: Wood, Brian J <brian.j.wood@intel.com>
Tested-by: Wood, Brian J <brian.j.wood@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>