[COMMON] fimc-is2: modify fimc_is_lib_isp_shot return type

[COMMON] fimc-is2: modify fimc_is_lib_isp_shot return type

 - for result from DDK, modified type void -> int

 PR JIRA ID: CPR-856

CRs-fixed: (CR)

Change-Id: I4a8a759738ff3e1687f39da9ca48385888f563c1
Signed-off-by: Wooyeon Kim <wooy88.kim@samsung.com>
Reviewed-on: https://gerrit.mot.com/1326262
SLTApproved: Slta Waiver
SME-Granted: SME Approvals Granted
Tested-by: Jira Key
Reviewed-by: Dawei Wang <wangdw10@motorola.com>
Reviewed-by: Zhichao Chen <chenzc2@motorola.com>
Submit-Approved: Jira Key