Camera3: Support burst input reprocessing

1) Do not restart postprocessor in the middle of the
session to simultaneously support both input reprocessing
and offline postprocessing
2) Allocate max inflight number of metatada buffers to map
the input metadata buffer to the pproc. Earlier only one was
allocated which meant we could only service one input request at
a time

Bug: 22639852

Change-Id: I6168c3a6675f7dc0dcf1b332cb3f419f3bc39cc9
2 files changed