EHCI: HSIC: Add support to vote for SVS digital voltage

HSIC HW can operate at SVS digital voltage when it is active.
Currently HSIC is voting for 120Mhz SFAB and 64Mhz DFAB clock
frequencies. Clock frequencies are directly proportional to SVS
voltage. If DFAB is running at 64Mhz or SFAB is running at 120Mhz
or higher SVS is not possible even though HSIC votes for it. Hence
do not vote for SFAB clock frequency and only vote for 32Mhz for
DFAB in order to allow SVS to happen. Voting for SVS voltage reduces
current consumption by 3mA in HSDPA network.

Change-Id: I8a6844efbbe90a8ea118be8450f8210717c2641b
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>