ath: rename ath_reg_apply_active_scan_flags() to ath_reg_apply_ir_flags()

This also applies the no-ibss flag to the channels or clears it.
The idea here is to clarify no initiated radiation should be
allowed on these channels.

Cc: smihir@qti.qualcomm.com
Cc: tushnimb@qca.qualcomm.com
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>