MLK-16753-7 imx: mx6sx: add optee support

MLK-16753-7 imx: mx6sx: add optee support

Add different defconfigs.
Enable Trustzone.
Update env to runtime boot OP-TEE.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
(cherry picked from commit 7c93e616d69f57668fb7e5ac24d8f7fa98dbe1f2)
(cherry picked from commit eb9063ee64bc30f51a20eec9da0750b0e82f3799)
(cherry picked from commit 580e0b29ca6501f706af6140357019e7f83692dd)
(cherry picked from commit c86df3e535c9528e43f36bfb8d362ca24f71098a)
(cherry picked from commit 306ccb6547769e79d2ee81a66fb993e467d87f02)
(cherry picked from commit 3443579fc35dca74c6ee295aacde911c901f6566)