The qspi clock divisor is incorrectly set to twice the value it should
have, possibly because it has been computed based on PLL1 as the clock
parent instead of PLL1 / 2 (the datasheets specifies the qspi nominal
frequencies, not the divisor values). Fix it.

This bug introduced in v3.14-rc1 breaks various devices on the Lager and
Kolesh shmobile boards and should thus be considered as a regression for
which a fix during the -rc series is appropriate.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>