ath9k_hw: cleanup MCI gpm offset state

Add utility functions to get and test GPM offset and
remove MCI_STATE*_GPM_OFFSET states.

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
4 files changed