ARM64:ILP32: work around the compilation error due to mainline changes

Commit 9648606 "arm64: Remove asm/syscalls.h" removed the header file
which the patch "ARM64:ILP32: Fix signal return for ILP32 when the user
modified the signal stack" was using.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
2 files changed