msm: vidc: update video dimensions during port reconfiguration

During a decode session, video output port can go through
reconfiguration. As a result, update the reconfig dimension
when client calls for g_fmt on output port.

Change-Id: Ib5f5866acbdfe107ba4693b8b94498d42f74b312
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>