soc: nxp: mcxn: configure CPU1 TrustZone access level

Configures AHBSC MASTER_SEC_LEVEL register for the cpu1 before cpu1 is
enabled.  By default, this gives CPU1 secure and privileged access to
the rest of the SOC, same as CPU0.

Signed-off-by: Derek Snell <derek.snell@nxp.com>