QCamera2: Return Error when deferred allocation fails

Issue:
In some race conditions, metadata/snapshot/postview
deferred allocation fails but still mm_stream_init_bufs
trying to access allocated buffers and resulting in
FATAL exception.

Fix:
Initialize mRegFlags & mBufDefs to NULL during stream
constructor and check same in get_bufs_deffered(),
If its NULL, pass it to calling function.

Change-Id: I283178b28354c71e432db2382b468df1fe4e5d0b
1 file changed