ARM: dts: msm: Add support for 4K X 2K encoding and playback for MSM8974Pro

MSM8974Pro supports true 4K X 2K video playback and encoding which is 4096
X 2160P at 30 fps . To support this the max MB count needs to be updated.
This change updates the same.

Change-Id: I10240f2bdcc6c6e2110bc72b7dff47aa6e1f5b77
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>