soc: imx8m: Correct i.MX8MP UID fuse offset

Correct i.MX8MP UID fuse offset according to fuse map:

UID_LOW: 0x420
UID_HIGH: 0x430

Fixes: fc40200e ("soc: imx: increase build coverage for imx8m soc driver")
Fixes: 18f662a7

 ("soc: imx: Add i.MX8MP SoC driver support")
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>