rt2x00: rt2800lib: fix RF registers for RT5390/RT5392

Update rf registers to use the same values that the MediaTek/Ralink
reference driver DPO_RT5572_LinuxSTA_2.6.1.3_20121022 uses.

References:
  RF5390RegTable in chips/rt5390.c
  RF5392RegTable in chips/rt5390.c

Tested on TP-Link TL-WN727N and D-Link DWA-140 Rev.b3 usb wifi dongles.

Signed-off-by: Kevin Lo <kevlo@kevlo.org>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: John W. Linville <linville@tuxdriver.com>