ARM: dts: msm: Add regulator cooling devices for SDXpoorwills

Add CX and MX regulator cooling devices for SDXPoorwills. These
regulator cooling devices will be used to place a floor restriction at
low temperatures.

Change-Id: I673d1da4cea9815f2476a13a46003fcb87dbc01f
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>