msm: vidc: Initialize max instances count

For various video platform data, initialize it with
the default count of 16. For specific platform, the
same can be overwritten to desired value.

Change-Id: I8a0ebe8a4dea4b1ea30028e170992e70cd6d835b
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>