tests: code_relocation: update test filters

ITCM relocation tests depends on MINIMAL_LIBC and when using Zephyr SDK
the default is PICOLIBC for mr_canhubk3 board, so explicitly select it.
Also the NXP S32 platforms don't have NXP MPU, so remove it.

For frdm_k64f the ITCM relocation test is not executed, so remove the
unnecesary filter CONFIG_MINIMAL_LIBC.

Signed-off-by: Manuel Argüelles <manuel.arguelles@nxp.com>