Clock code was changed to use clk_prepare_enable in:

b707c65 dma/ste_dma40: Fixup clock usage during probe

but clk_disable on probe fail path was not updated.  This patch fix this
by using clk_disable_unprepare in place of clk_disable.
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NFabio Baltieri <fabio.baltieri@linaro.org>