ARM: imx6q: use pll2_pfd2_396m as the enfc_sel's parent

The gpmi-nand driver can support the ONFI nand chip's EDO (extra data out)
mode in the asynchrounous mode. In the asynchrounous mode 5, the gpmi
needs 100MHz clock for the IO. But with the pll2_pfd0_352m, we can not
get the 100MHz clock.

So choose pll2_pfd2_396m as enfc_sel's parent.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>