qtnfmac: let wifi card handle channel switch request to the same chan

No reason to verify channel switch request in driver, it can simply be
forwarded to wireless device. Device can perform required checks and
return appropriate error code, and driver may not even have information
on current operational channel.

Signed-off-by: Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>