ath9k: Fix mismerge of do-not-access-hw-on-IRQ-reset

Restore the revert made by 5b1e4ee1cad:
	ath9k: revert do-not-access-hw-on-IRQ-reset

And revert the companion to the original patch that was reverted:
	ath9k: fix-race-condition-in-irq-processing-during-hardware-reset
by removing irq disabling in ath_reset_internal.

Fixes b/22067911

Change-Id: Ide6f927f4fd0b0e7b37632e9543ddf3af43abffb
1 file changed