imx8mq: update chip revision method for B1

i.MX8MQ B1's chip revision is identified by reading
OCOTP offset 0x40, the magic number 0xff0055aa is
for B1.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
(cherry picked from commit 701e7961dfe568d724343c4e2897907cb34cc276)
2 files changed