ARM: dts: imx27: Fix sram node

[ Upstream commit 2fb7b2a2f06bb3f8321cf26c33e4e820c5b238b6 ]

Per sram.yaml, address-cells, size-cells and ranges are mandatory.

Pass them to fix the following dt-schema warnings:

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>