soc/tegra: Make regulator couplers depend on CONFIG_REGULATOR

The regulator coupler drivers now use regulator-driver API function that
isn't available during compile-testing. Make regulator coupler drivers
dependent on CONFIG_REGULATOR in Kconfig.

Fixes: 03978d42 ("soc/tegra: regulators: Bump voltages on system reboot")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/soc/tegra/Kconfig

@@ -15,7 +15,7 @@ config ARCH_TEGRA_2x_SOC
 	select PL310_ERRATA_769419 if CACHE_L2X0
 	select SOC_TEGRA_FLOWCTRL
 	select SOC_TEGRA_PMC
-	select SOC_TEGRA20_VOLTAGE_COUPLER
+	select SOC_TEGRA20_VOLTAGE_COUPLER if REGULATOR
 	select TEGRA_TIMER
 	help
 	  Support for NVIDIA Tegra AP20 and T20 processors, based on the
@@ -29,7 +29,7 @@ config ARCH_TEGRA_3x_SOC
 	select PL310_ERRATA_769419 if CACHE_L2X0
 	select SOC_TEGRA_FLOWCTRL
 	select SOC_TEGRA_PMC
-	select SOC_TEGRA30_VOLTAGE_COUPLER
+	select SOC_TEGRA30_VOLTAGE_COUPLER if REGULATOR
 	select TEGRA_TIMER
 	help
 	  Support for NVIDIA Tegra T30 processor family, based on the
@@ -155,7 +155,9 @@ config SOC_TEGRA_POWERGATE_BPMP
 config SOC_TEGRA20_VOLTAGE_COUPLER
 	bool "Voltage scaling support for Tegra20 SoCs"
 	depends on ARCH_TEGRA_2x_SOC || COMPILE_TEST
+	depends on REGULATOR
 
 config SOC_TEGRA30_VOLTAGE_COUPLER
 	bool "Voltage scaling support for Tegra30 SoCs"
 	depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST
+	depends on REGULATOR