ARM: dts: msm: Add cooling device property to msm8953 msm gpu

Add cooling-cells property to msm gpu for msm8953. This enables
the gpu cooling device to be referenced in a thermal zone definition.

Change-Id: I464dd4baf178d86a2afcb16283d584817a9dc9d9
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>