ARM: dts: msm: Set LDO_6 as always on for SKUT1

SKUT1 uses LDO_6 for SMB1358 and accelerometer which
keep working with system in standby (e.g.: charging).
If LDO_6 gets disabled by mdss and touchscreen on screen
off, causing SMB1358 and MC3210 devices to not be able to
use I2C. Set LDO_6 as always on to fix this issue.

Change-Id: Ie896f0d867f829e4f481a9f2c6b33a0e08ff12b3
Signed-off-by: Gustavo Solaira <gustavos@codeaurora.org>