x86: Rename trap_no to trap_nr in thread_struct

There are precedences of trap number being referred to as
trap_nr. However thread struct refers trap number as trap_no.
Change it to trap_nr.

Also use enum instead of left-over literals for trap values.

This is pure cleanup, no functional change intended.

Suggested-by: Ingo Molnar <mingo@eltu.hu>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Linux-mm <linux-mm@kvack.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120312092555.5379.942.sendpatchset@srdronam.in.ibm.com
[ Fixed the math-emu build ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 7718541..9b86812 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -28,6 +28,7 @@
 #include <linux/regset.h>
 
 #include <asm/uaccess.h>
+#include <asm/traps.h>
 #include <asm/desc.h>
 #include <asm/user.h>
 #include <asm/i387.h>
@@ -269,7 +270,7 @@
 			FPU_EIP = FPU_ORIG_EIP;	/* Point to current FPU instruction. */
 
 			RE_ENTRANT_CHECK_OFF;
-			current->thread.trap_no = 16;
+			current->thread.trap_nr = X86_TRAP_MF;
 			current->thread.error_code = 0;
 			send_sig(SIGFPE, current, 1);
 			return;
@@ -662,7 +663,7 @@
 void math_abort(struct math_emu_info *info, unsigned int signal)
 {
 	FPU_EIP = FPU_ORIG_EIP;
-	current->thread.trap_no = 16;
+	current->thread.trap_nr = X86_TRAP_MF;
 	current->thread.error_code = 0;
 	send_sig(signal, current, 1);
 	RE_ENTRANT_CHECK_OFF;