msm: vidc: Move metadata shared input mem to firmware heap.

Metadata shared input is used to communicate between the
video core and video driver. Allocate it from firmware
heap for specific targets as MFC command heap size is
limited.

CRs-Fixed: 450118
Change-Id: I3d04cf6dd498ae67adcec7a8cba513bd7932d158
Signed-off-by: Shobhit Pandey <cshopan@codeaurora.org>
Signed-off-by: Deepak Verma <dverma@codeaurora.org>