regulator: rpi-panel-v2: Add missing GPIOLIB dependency

Add missing GPIOLIB dependency reported by the LKP test robot.
This fixes the following report:

"
kismet warnings: (new ones prefixed by >>)
>> kismet: WARNING: unmet direct dependencies detected for GPIO_REGMAP when selected by REGULATOR_RASPBERRYPI_TOUCHSCREEN_V2
WARNING: unmet direct dependencies detected for GPIO_REGMAP
Depends on [n]: GPIOLIB [=n]
Selected by [y]:
- REGULATOR_RASPBERRYPI_TOUCHSCREEN_V2 [=y] && REGULATOR [=y] && I2C [=y]
"

Fixes: d49305862fdc ("regulator: rpi-panel-v2: Add regulator for 7" Raspberry Pi 720x1280")
Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Signed-off-by: Marek Vasut <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/Kconfig

···
 
 config REGULATOR_RASPBERRYPI_TOUCHSCREEN_V2
 	tristate "Raspberry Pi 7-inch touchscreen panel V2 regulator"
+	depends on GPIOLIB
 	depends on I2C
 	select GPIO_REGMAP
 	select REGMAP_I2C