camera2: use bulk get methods while unmarshalling primitives.

Bug: 239167817

Test: GCA (validity)
Test: Camera CTS
Test: profiling results mentioned in b/239167817

Change-Id: I6954a81d49be6d8a0746301e544b1772444ee746
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>