rt2800pci: convert to use struct rt2800_ops methods

Add chipset registers access abstraction layer and prepare for later
code unification.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/rt2x00/rt2800pci.c
Simple merge

diff --cc drivers/net/wireless/rt2x00/rt2800pci.h
Simple merge