gpio: loongson: Switch 2K2000/3000 GPIO to BYTE_CTRL_MODE

gpio: loongson: Switch 2K2000/3000 GPIO to BYTE_CTRL_MODE

The manuals of 2K2000 says both BIT_CTRL_MODE and BYTE_CTRL_MODE are
supported but the latter is recommended.  Also on 2K3000, per the ACPI
DSDT the GPIO controller is compatible with 2K2000, but it fails to
operate GPIOs 62 and 63 (and maybe others) using BIT_CTRL_MODE.
Using BYTE_CTRL_MODE also makes those 2K3000 GPIOs work.

Fixes: 3feb70a61740 ("gpio: loongson: add more gpio chip support")
Cc: stable@vger.kernel.org
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/20251128075033.255821-1-xry111@xry111.site
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>