ARM: rmobile: Enable cache command on Gen3

This patch enables the cache command, mostly for convenience of testing.

Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
diff --git a/arch/arm/mach-rmobile/Kconfig b/arch/arm/mach-rmobile/Kconfig
index ac08d6e..d82023a 100644
--- a/arch/arm/mach-rmobile/Kconfig
+++ b/arch/arm/mach-rmobile/Kconfig
@@ -12,6 +12,7 @@
 	bool "Renesas ARM SoCs R-Car Gen3 (64bit)"
 	select ARM64
 	select PHY
+	select CMD_CACHE
 
 endchoice