ADC calibrations cannot run on 5 GHz with fast clock enabled. They
need to be disabled, otherwise they'll hang and IQ mismatch calibration
will not be run either.
Signed-off-by: Felix Fietkau <nbd@openwrt.org> Reported-by: Adrian Chadd <adrian@freebsd.org> Cc: stable@kernel.org Signed-off-by: John W. Linville <linville@tuxdriver.com>