ARM: dts: msm: Add new property to specify OCMEM size

OCMEM is required by video hardware to deliver optimal
performance mostly at higher resolutions/fps. For targets
which have low specifications, OCMEM is not needed or not
needed as much as for higher targets. This change adds the
property to dtsi file to specify the size of OCMEM.

Change-Id: I65ae271bc73d302975957727a95461c7388727f6
Signed-off-by: Ashray Kulkarni <ashrayk@codeaurora.org>
Signed-off-by: Vinay Kalia <vkalia@codeaurora.org>
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>