gpio: qixis: select CONFIG_REGMAP_MMIO

The regmap drivers need to be selected by each user, without that there
can be configurations that fail to link:

x86_64-linux-ld: drivers/gpio/gpio-qixis-fpga.o: in function `qixis_cpld_gpio_probe':
gpio-qixis-fpga.c:(.text+0x13a): undefined reference to `__devm_regmap_init_mmio_clk'

Fixes: e885002 ("gpio: add QIXIS FPGA GPIO controller")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20251204094928.1031494-1-arnd@kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Author: arndb

drivers/gpio/Kconfig

@@ -1568,6 +1568,7 @@ config GPIO_QIXIS_FPGA
 	tristate "NXP QIXIS FPGA GPIO support"
 	depends on MFD_SIMPLE_MFD_I2C || COMPILE_TEST
 	select GPIO_REGMAP
+	select REGMAP_MMIO
 	help
 	  This enables support for the GPIOs found in the QIXIS FPGA which is
 	  integrated on some NXP Layerscape boards such as LX2160ARDB and