In some cases the limit may be the same as reg->power_limit, but the
actual value that the hardware uses is not up to date. In that case, a
wrong value for current tx power is tracked internally.
Fix this by unconditionally updating it.
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>