MLK-21291 imx8mm: evk: not restrict uart4 when enabling jailhouse

MLK-21291 imx8mm: evk: not restrict uart4 when enabling jailhouse

When booting dual linux with jailhouse, inmate linux will use
the 2nd uart, so not restrict access the uart for jailhouse case.

The best solution would be using SIP call to ATF, for simplicity,
directly modify the RDC register.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
(cherry picked from commit b22b70ff0b5bbacea7383bde9e8893bb504199c3)
(cherry picked from commit e5768d04b57599ef8d5fcb4664d87b7c3ba50feb)
(cherry picked from commit 0a7bb85d05f567274d54b4aaf6d061b0b1c03b33)
(cherry picked from commit fb97a542a5c74cb57ca9dcc10c960fde4f4bc209)