ENGR00173869-3: i.mx6: add the cpu_is_mx6dl() support
In order to support one image for i.mx6q and i.mx6dl, we introduce
the below functions by diff the value reading from ANATOP ID register.
cpu_is_mx6q() and cpu_is_mx6dl()
The layout for the register defines:
Major Minor
i.MX6Q1.1: 6300 01
i.MX6Q1.0: 6300 00
i.MX6DL1.0: 6100 00
For the common bits shared across all i.mx6 ports, we can use:
cpu_is_mx6() for it.