ARM: imx: Add revision support for i.MX7ULP revision 2.2

On i.MX7ULP revision 2.2, the value is 3, so add support for this
revision, otherwise, it will use default revision of 1.0 which is
incorrect.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>