As with the previous commit, before a clock can be used it must be prepared
for use. Change from clk_enable() and clk_disable() to the versions of the
calls which also prepare and un-prepare the clocks.

Will fix warnings from the clock code when this is used.
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@linaro.org>