arm64: add SIGSYS siginfo for compat task

Note: This patch is from v6 of Takahiro's proposed
"arm64: add seccomp support" patchset (leecam@google.com)

SIGSYS is primarily used in secure computing to notify tracer.
This patch allows signal handler on compat task to get correct information
with SA_SYSINFO specified when this signal is delivered.

Signed-off-by: AKASHI Takahiro <takahiro.akashi <at> linaro.org>
Git-commit: 77227239d20ac6381fb1aee7b7cc902f0d14cd85
Git-repo: https://android.googlesource.com/kernel/common.git


Change-Id: Ie827e4e7202d6ab96d0185ec6a22625b1c933bac
Signed-off-by: Ian Maund <imaund@codeaurora.org>
Signed-off-by: Ravi Kumar Siddojigari <rsiddoji@codeaurora.org>
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>