ARM: tegra: Guard pin controller code with a Kconfig symbol

Pin controller 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/board2.c b/arch/arm/mach-tegra/board2.c
index b940772..ce1c934 100644
--- a/arch/arm/mach-tegra/board2.c
+++ b/arch/arm/mach-tegra/board2.c
@@ -25,8 +25,10 @@
 #if IS_ENABLED(CONFIG_TEGRA_CLKRST)
 #include <asm/arch/clock.h>
 #endif
+#if IS_ENABLED(CONFIG_TEGRA_PINCTRL)
 #include <asm/arch/funcmux.h>
 #include <asm/arch/pinmux.h>
+#endif
 #include <asm/arch/tegra.h>
 #ifdef CONFIG_TEGRA_CLOCK_SCALING
 #include <asm/arch/emc.h>