ENGR00173869-9: i.mx6dl: add the misc drivers support

ENGR00173869-9: i.mx6dl: add the misc drivers support

This patch change is very trivial and simply just add
cpu_is_mx6dl() or using cpu_is_mx6 to replace cpu_is_mx6q

each driver owner will check it and adjust it accordingly later,
such as sdhc etc.

Signed-off-by: Jason Liu <r64343@freescale.com>