mmc: put the led blinking code after clock ungating

Since mmc clock gating can also be used as a power gating
tip, it's better to put the led blinking after having
ungated the clock.

Signed-off-by: Pierre Tardy <pierre.tardy@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>