um: Handle tracehook_report_syscall_entry() result

tracehook_report_syscall_entry() is allowed to fail,
in case of failure we have to abort the current syscall.

Change-Id: I906689be8f24b8fbb46d7acf5c93abf36795370d
Signed-off-by: Richard Weinberger <richard@nod.at>
Git commit: 5334cdae407a5778a297a98a75ca61140e37ebfa
Git repo: https://github.com/torvalds/linux.git


Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>