LF-95-2 arm64: imx8qm-ss-mipi.dtsi: Correct MIPI CSR address and size

LF-95-2 arm64: imx8qm-ss-mipi.dtsi: Correct MIPI CSR address and size

The spec tells us that the CSR start address is 0x1000 and end address
is 0x1FFF according to the subsystem start address.  However, it turns
out some space are inaccessible, which would accidently cause system
hang via kernel regmap debugfs.  This patch corrects the MIPI CSR
start address and chooses a sensible size, which makes sure all exposed
registers are accessible.

Reviewed-by: Sandor Yu <Sandor.yu@nxp.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>