ARM: dts: enable auto mode for MSM8974 based devices

Enable auto mode for MSM8974 based devices. Auto mode is enabled
only in single phase configuration, allows us to switch between
pfm and pwm mode based on the load profile.

Change-Id: I1901420ff4720aa911c75b7f86ef725273b30ed1
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>