We currently register the BCMA core even if the GPIO portions
fail. There is no reason for this: the GPIO should register
just fine, if it fails the BCMA driver should fail.

We already gracefully handle the case where the GPIO driver is
not compiled in.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221028093000.239020-1-linus.walleij@linaro.org