imx: clock support enet2 anatop clock support

imx: clock support enet2 anatop clock support

To i.MX6SX/UL, two ethernet interfaces are supported.
Add ENET2 clock support:
1. Introduce a new input parameter "fec_id", only 0 and 1 are allowed.
   To value 1, only i.MX6SX/UL can pass the check.
2. Modify board code who use this api to follow new api prototype.

Signed-off-by: Peng Fan <[email protected]>
Cc: Heiko Schocher <[email protected]>
Cc: Fabio Estevam <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Nikolaos Pasaloukos <[email protected]>
Cc: Stefano Babic <[email protected]>
Reviewed-by: Stefan Roese <[email protected]>