ARM: dts: msm: Add device node for mem-acc-regulator on msm8926-v2

The mem-acc-regulator adds support to select power-mode
for the memory accelerator. Specify the device node properties
for this regulator. Also, pass its handle to the CPR driver.

Change-Id: Ia9789116b2e14a045aa4f9c64e18f2243ef43aa9
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>