ARM: dts: msm: keep UFS phy regulator always on for SM6150

We may see some glitch on UFS host TX when turning on/off the UFS PHY
regulator, this change keeps this regulator always ON but still tries
to keep the regulator in LPM mode.

Change-Id: Ifcf6a7277db40bbdccba46819bcb553df8e54bcd
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Ziqi Chen <ziqichen@codeaurora.org>