parisc: Add PDC PAT cell_info() and pd_get_pdc_revisions() functions

Add wrappers for the PDC_PAT_CELL_GET_INFO and
PDC_PAT_PD_GET_PDC_INTERF_REV PAT PDC subfunctions.

Both provide access to the PAT capability bitfield which can guide us if
simultaneous PTLBs are allowed on the bus, and if firmware will
rendezvous all processors within PDCE_Check in case of an HPMC.

Signed-off-by: Helge Deller <deller@gmx.de>