openrisc: sanitize use of orig_gpr11

The pt_regs struct had both a 'syscallno' field and an 'orig_gpr11' field
and it wasn't really clear how these were supposed to be used.  This patch
removes the syscallno field altogether and makes orig_gpr11 work more
like other architectures: keep track of syscall number in progress or
hold -1 for non-syscall exceptions.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
diff --git a/arch/openrisc/kernel/ptrace.c b/arch/openrisc/kernel/ptrace.c
index 7259047..6deacb6 100644
--- a/arch/openrisc/kernel/ptrace.c
+++ b/arch/openrisc/kernel/ptrace.c
@@ -188,11 +188,11 @@
 		 */
 		ret = -1L;
 
-	audit_syscall_entry(audit_arch(), regs->syscallno,
+	audit_syscall_entry(audit_arch(), regs->gpr[11],
 			    regs->gpr[3], regs->gpr[4],
 			    regs->gpr[5], regs->gpr[6]);
 
-	return ret ? : regs->syscallno;
+	return ret ? : regs->gpr[11];
 }
 
 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)