mmc: host: omap_hsmmc: don't use ->set_power to set initial regulator state

If the regulator is enabled on boot (checked using regulator_is_enabled),
invoke regulator_enable() so that the usecount reflects the correct
state of the regulator and then disable the regulator so that the
initial state of the regulator is disabled. Avoid using ->set_power,
since set_power also takes care of setting the voltages which is not
needed at this point.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>