ARM: omap3: clock: fix wrong container_of in clock36xx.c

omap36xx_pwrdn_clk_enable_with_hsdiv_restore expects the parent hw of
the clock to be a clk_hw_omap. However, looking at cclock3xxx_data.c,
all concerned clock have parent defined as clk_divider.  Fix the
function to use clk_divider.  Tested with 3.9 on dm3730.

Signed-off-by: Jean-Philippe François <jp.francois@cynove.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Paul Walmsley <paul@pwsan.com>