mmc: host: omap_hsmmc: remove CONFIG_REGULATOR check

Now that support for platforms which have optional regulator is added,
remove CONFIG_REGULATOR check in omap_hsmmc.

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>