ARM: 6409/1: davinci: map sram using MT_MEMORY_NONCACHED instead of MT_DEVICE

On Davinci SRAM is mapped as MT_DEVICE becasue of the section
mapping pre-requisite instead of intended MT_MEMORY_NONCACHED

Since the section mapping limitation gets fixed with first
patch in this series, the MT_MEMORY_NONCACHED can be used now.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>