The QCA953x only supports 25 MHz refclk, however some OEMs set an
invalid bootstrap value for the REF_CLK option, which would break the
clock detection in ath9k.
Force the QCA953x refclk to 25MHz in ath9k, as this is (according to the
datasheet) the only valid frequency.
Signed-off-by: David Bauer <mail@david-bauer.net>
4c6fe32468