audit: inline audit_syscall_entry to reduce burden on archs

Every arch calls:

if (unlikely(current->audit_context))
	audit_syscall_entry()

which requires knowledge about audit (the existance of audit_context) in
the arch code.  Just do it all in static inline in audit.h so that arch's
can remain blissfully ignorant.

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index f527586..9d82ed4 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -740,12 +740,11 @@
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_enter(regs, regs->gprs[2]);
 
-	if (unlikely(current->audit_context))
-		audit_syscall_entry(is_compat_task() ?
-					AUDIT_ARCH_S390 : AUDIT_ARCH_S390X,
-				    regs->gprs[2], regs->orig_gpr2,
-				    regs->gprs[3], regs->gprs[4],
-				    regs->gprs[5]);
+	audit_syscall_entry(is_compat_task() ?
+				AUDIT_ARCH_S390 : AUDIT_ARCH_S390X,
+			    regs->gprs[2], regs->orig_gpr2,
+			    regs->gprs[3], regs->gprs[4],
+			    regs->gprs[5]);
 	return ret ?: regs->gprs[2];
 }