[ARM] 4134/1: Add generic support for outer caches

The outer cache can be L2 as on RealView/EB MPCore platform or even L3
or further on ARMv7 cores. This patch adds the generic support for
flushing the outer cache in the DMA operations.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index aade2f7..a84eed9 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -609,3 +609,6 @@
 	  Forget about fast user space cmpxchg support.
 	  It is just not possible.
 
+config OUTER_CACHE
+	bool
+	default n