wifi: mwifiex: Drop unused headers

The mwifiex driver include two legacy GPIO headers but does
not use symbols from any of them.

The driver does contain some "gpio" handling code, but this
is some custom GPIO interface, not the Linux GPIO.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240131-descriptors-wireless-v1-4-e1c7c5d68746@linaro.org