fimc-is2: fix ITS scene0 test_read_write

fimc-is2: fix ITS scene0 test_read_write

update exposure metadata update timing to fix exposure
mismatch for raw and jpg case

Change-Id: I7bf61b8d89da819ce8974e2c7f887c3ed6ed2e3a
Signed-off-by: wangdw10 <wangdw10@mt.com>
Reviewed-on: https://gerrit.mot.com/1433855
SME-Granted: SME Approvals Granted
SLTApproved: Slta Waiver
Tested-by: Jira Key
Reviewed-by: Biming Li <libm1@motorola.com>
Reviewed-by: Dawei Wang <wangdw10@motorola.com>
Reviewed-by: Zhichao Chen <chenzc2@motorola.com>
Submit-Approved: Jira Key