intel_scu_ipc: Support Medfield processors

Changes to work on bothMmoorestown and Medfield
New pci id added for Medfield
Return type of ipc_data_readl chnaged from u8 to u32

Signed-off-by: Sreedhara DS <sreedhara.ds@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>