[ARM] Move syscall saving out of the way of utrace

utrace removes the ptrace_message field in task_struct.  Move our use
of this field into a new member in thread_info called "syscall"

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index e594b84..13af400 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -779,8 +779,8 @@
 			break;
 
 		case PTRACE_SET_SYSCALL:
+			task_thread_info(child)->syscall = data;
 			ret = 0;
-			child->ptrace_message = data;
 			break;
 
 #ifdef CONFIG_CRUNCH
@@ -817,7 +817,7 @@
 	ip = regs->ARM_ip;
 	regs->ARM_ip = why;
 
-	current->ptrace_message = scno;
+	current_thread_info()->syscall = scno;
 
 	/* the 0x80 provides a way for the tracing parent to distinguish
 	   between a syscall stop and SIGTRAP delivery */
@@ -834,5 +834,5 @@
 	}
 	regs->ARM_ip = ip;
 
-	return current->ptrace_message;
+	return current_thread_info()->syscall;
 }