arm: mxs: be more careful when enabling gpmi_clk

The data sheet says that the DIV field cannot change while the CLKGATE
bit is set or modified. So do it a little more carefully, by first
clearing the bit, waiting for that to appear, then setting the DIV
field.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
1 file changed