MLK-20259 ARM: imx: add soc revision check for i.MX7ULP

MLK-20259 ARM: imx: add soc revision check for i.MX7ULP

i.MX7ULP SoC revision is available from B0, the SIM_JTAG_ID
register bit[31:28] indicates SoC revision as below:

4b'0001        B0
4b'0010        B1

This register is NOT available on A0, tested on B1 chip
as below:

root@imx7ulpevk:~# cat /sys/devices/soc0/revision
2.1

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Bai Ping <ping.bai@nxp.com>
Tested-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>