USB: OTG: MSM: Enable VDD CX regulator voltage setting for all configs

Enable VDD CX regulator voltage setting even for kernel configs
without PM_SLEEP enabled.  This is required so that USB functions
without power management.

Previously disabling power management also incorrectly disables USB.

Change-Id: I81d04cbca2e956e12fe40eeb97fbaab8c2ec1fd2
Signed-off-by: David Ng <dave@codeaurora.org>