QCamera2/HAL3: Increase inflight request count for 60FPS encode

With 16.67 ms time per frame expected, the current in-flight request count
is insufficient. Increase it to 6 to avoid the frame drops.

Ack-by: Ashvin Deodhar

BUG=28313712
CRs-Fixed: 1020354

Change-Id: I6d9fe11402e53eb3b11be42a30a86f76a9c4e0ff
3 files changed