Add arch-syscall.h dependency for generating sysd-syscalls file

After using "make update-syscall-lists" to update arch-syscall.h for
new kernel versions, sysd-syscalls will not be not be regenerated.
This will cause a compile error because the new data is not being
picked up.

Fixes commit a1bd5f86
("Linux: Use system call tables during build").

Reviewed-by: Florian Weimer <fweimer@redhat.com>