mmc: msm_sdcc: set IO_PAD_PWR_SWITCH bit based on IO voltage level

SDCC4 controller has IO_PAD_PWR_SWITCH control bit in MCI_CLK register.
Driver should set this bit to 1 if the IO voltage level is within
low voltage range (1.7v - 1.9v) else clear it.

But driver sets this bit to 1 only if the MMC core layer initiates
the voltage switch sequence. So if voltage switch sequence is not
initiated (which is the case with non UHS-I cards) then even if
the IO voltage level is within low voltage range, IO_PAD_PWR_SWITCH
bit remains cleared.

This change checks the IO voltage level and based on that sets the
IO_PAD_PWR_SWITCH bit.

CRs-Fixed: 386445
Change-Id: Id0648b0f87ea9bcc942e855e30da810e0fe5ebf5
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>