Input: gpio-keys - convert to dev_err_probe()

Use the dev_err_probe() helper, instead of open-coding the same
operation.

While at it, invert the error checking logic to simplify code flow.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/d225a837c50e2b19a41555a8f7ce0f94b1689aa4.1689600353.git.geert+renesas@glider.be


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>