mmc: sdhci-msm: Add dual voltage capability

SDCC5 controller doesn't advertise 1.8v capability by default.
Dual voltage capability is required for SD3.0 support. Add this
capability for controllers that support this based on
device tree configuration.

Change-Id: Ie4cd6db2e7230bc22cd393c8e37d99f49c777cd0
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>