s390/seccomp: include generic seccomp header file

Fixes this build error on linux-next:

kernel/seccomp.c: In function '__secure_computing_strict':
kernel/seccomp.c:526:3: error: implicit declaration of function
'get_compat_mode1_syscalls'

The retrieval of compat syscall numbers were moved into inline function
defined in asm-generic header but the asm-generic header is not being
used by s390.

[[e-mail]]: even though the build error will trigger
only in the next merge window it makes sense to include the generic
header file already now.

Fixes: ("seccomp: Get compat syscalls from asm-generic header")
Cc: Matt Redfearn <[e-mail]>
Signed-off-by: Sudip Mukherjee <[e-mail]>
Signed-off-by: Heiko Carstens <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/seccomp.h

···
 #define __NR_seccomp_exit_32	__NR_exit
 #define __NR_seccomp_sigreturn_32 __NR_sigreturn
 
+#include <asm-generic/seccomp.h>
+
 #endif	/* _ASM_S390_SECCOMP_H */