[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>

include/asm-arm/thread_info.h

@@ -57,6 +57,7 @@ struct thread_info {
 	__u32			cpu;		/* cpu */
 	__u32			cpu_domain;	/* cpu domain */
 	struct cpu_context_save	cpu_context;	/* cpu context */
+	__u32			syscall;	/* syscall number */
 	__u8			used_cp[16];	/* thread used copro */
 	unsigned long		tp_value;
 	struct crunch_state	crunchstate;