ARM: dts: imx25: Fix sram node

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

Pass them to fix the following schema warnings:

sram@78000000: '#address-cells' is a required property
from schema $id: http://devicetree.org/schemas/sram/sram.yaml#
sram@78000000: '#size-cells' is a required property
from schema $id: http://devicetree.org/schemas/sram/sram.yaml#
sram@78000000: 'ranges' is a required property
from schema $id: http://devicetree.org/schemas/sram/sram.yaml#



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