parisc: Add break statements to pdc_pat_io_pci_cfg_read()

Dan Carpenter noticed that pdc_pat_io_pci_cfg_read() is problematic
because it's missing some break statements so it copies 4 bytes
regardless of whether you asked for only 1 or 2.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Helge Deller <deller@gmx.de>