We should not be ignoring -EPROBE_DEFER reported by
devm_gpiod_get_optional(), but report it as any other error to the upper
layers. While we are at it simplify check for the presence of reset GPIO
and instead of using IS_ERR_OR_NULL just use boolean.

Also do not return -ENOMEM from suspend handler when the device in
bootloader mode as that does not make sense and switch to -EBUSY instead.
Reported-by: Guenter Roeck <groeck@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>