Synchronize the uapi kernel header files which solves the broken
uapi export of pt_regs.  Because of arch-specific uapi headers,
extended the include path in the Makefile.

With this change, the test_verifier program compiles and runs successfully
on s390.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-and-tested-by: NThomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>