regulator: lp872x: Don't allow modular build

Fixes link failure due to devm_gpio_request_one()
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/Kconfig

@@ -20,6 +20,7 @@ menuconfig REGULATOR
 
 	  If unsure, say no.
 
+
 if REGULATOR
 
 config REGULATOR_DEBUG
@@ -225,7 +226,7 @@ config REGULATOR_LP3972
 	 on National Semiconductors LP3972 PMIC
 
 config REGULATOR_LP872X
-	tristate "TI/National Semiconductor LP8720/LP8725 voltage regulators"
+	bool "TI/National Semiconductor LP8720/LP8725 voltage regulators"
 	depends on I2C
 	select REGMAP_I2C
 	help