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/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index ab0f196..7786b60 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -560,10 +560,9 @@
 	}
 
 out:
-	if (unlikely(current->audit_context))
-		audit_syscall_entry(audit_arch(), regs->regs[2],
-				    regs->regs[4], regs->regs[5],
-				    regs->regs[6], regs->regs[7]);
+	audit_syscall_entry(audit_arch(), regs->regs[2],
+			    regs->regs[4], regs->regs[5],
+			    regs->regs[6], regs->regs[7]);
 }
 
 /*