[ARM] remove asm/ptrace.h from asm/thread_info.h

asm/thread_info.h doesn't need asm/ptrace.h, remove it.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/thread_info.h

@@ -24,7 +24,6 @@
 struct task_struct;
 struct exec_domain;
 
-#include <asm/ptrace.h>
 #include <asm/types.h>
 #include <asm/domain.h>