ARM: tegra20: Make MC optional in Kconfig

For bare minimal system.
Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/mach-tegra/Kconfig

@@ -20,8 +20,6 @@ config ARCH_TEGRA_2x_SOC
 	select PL310_ERRATA_727915 if CACHE_L2X0
 	select PL310_ERRATA_769419 if CACHE_L2X0
 	select CPU_FREQ_TABLE if CPU_FREQ
-	select MEMORY
-	select TEGRA20_MC
 	help
 	  Support for NVIDIA Tegra AP20 and T20 processors, based on the
 	  ARM CortexA9MP CPU and the ARM PL310 L2 cache controller

drivers/memory/Kconfig

@@ -21,8 +21,14 @@ config TI_EMIF
 	  temperature changes
 
 config TEGRA20_MC
-	bool
+	bool "Tegra20 Memory Controller(MC) driver"
+	default y
 	depends on ARCH_TEGRA_2x_SOC
+	help
+	  This driver is for the Memory Controller(MC) module available
+	  in Tegra20 SoCs, mainly for a address translation fault
+	  analysis, especially for IOMMU/GART(Graphics Address
+	  Relocation Table) module.
 
 config TEGRA30_MC
 	bool