On the i.MX6qp the enfc_sel mux is at bits 15-17, not on 16-17. Fix
this. During clock tree initialization we reparented the enfc_sel to:

	clk_set_parent(clks[IMX6QDL_CLK_ENFC_SEL], clks[IMX6QDL_CLK_PLL2_PFD2_396M]);

This resulted in a register setting 0b110 for the enfc_sel mux which is
reserved. Apparently this reserved setting resulted in the enfc clock
being driven from pll3_pfd3_454m. This means our enfc clock was the
factor 454/396 too high.

With b534f79112f0 ("clk: imx6: Fix procedure to switch the parent of
LDB_DI_CLK") we happened to disable pll3_pfd3_454m during init, so with
this commit NAND stopped working entirely on i.MX6qp.

Both issues are fixed with this patch

Fixes: b534f79112f0 ("clk: imx6: Fix procedure to switch the parent of LDB_DI_CLK")
Fixes: 92fd61d12723 ("clk: i.MX6: Fix enfc_sel for i.MX6dqp")

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>