ARM: tegra: Guard powergate code with a Kconfig symbol

Powergate code is not relevant on all Tegra SoC generations, so guard it
with a Kconfig symbol that can be selected by the generations that need
it.

This is in preparation for unifying Tegra186 code with the code used on
older generations.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index be20ac2..db91983 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -32,6 +32,9 @@
 config TEGRA_PINCTRL
 	bool
 
+config TEGRA_PMC
+	bool
+
 config TEGRA_COMMON
 	bool "Tegra common options"
 	select BINMAN
@@ -74,6 +77,7 @@
 	select TEGRA_MC
 	select TEGRA_NO_BPMP
 	select TEGRA_PINCTRL
+	select TEGRA_PMC
 
 config TEGRA_ARMV8_COMMON
 	bool "Tegra 64-bit common options"
@@ -122,6 +126,7 @@
 	select TEGRA_MC
 	select TEGRA_NO_BPMP
 	select TEGRA_PINCTRL
+	select TEGRA_PMC
 
 config TEGRA186
 	bool "Tegra186 family"