gpio: spacemit: Add missing MODULE_DEVICE_TABLE

The gpio-spacemit-k1 driver can be compiled as a module. Add missing
MODULE_DEVICE_TABLE so it can be matched by modalias and automatically
loaded by udev.

Fixes: d0055324 ("gpio: spacemit: add support for K1 SoC")
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250613-k1-gpio-of-table-v1-1-9015da8fdfdb@iscas.ac.cn


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>