ARC: Fix the typo in event identifier flags used by ptrace

orig_r8_IS_EXCPN and orig_r8_IS_BRKPT were same values due to a
copy/paste error. Although it looks bad and is wrong, it really doesn't
affect gdb working.

orig_r8_IS_BRKPT is the one relevant to debugging (breakpoints), since
it is used to provide EFA vs. ERET to a ptrace "stop_pc" request.

So when gdb has inserted a breakpoint, orig_r8_IS_BRKPT is already set,
and anything else (i.e. orig_r8_IS_EXCPN) becoming same as it, really
doesn't hurt gdb. The corollary case, could be nasty but nobody uses the
ptrace "stop_pc" request in that case

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/entry.h b/arch/arc/include/asm/entry.h
index 23daa32..eb2ae53 100644
--- a/arch/arc/include/asm/entry.h
+++ b/arch/arc/include/asm/entry.h
@@ -415,7 +415,7 @@
  *-------------------------------------------------------------*/
 .macro SAVE_ALL_EXCEPTION   marker
 
-	st      \marker, [sp, 8]
+	st      \marker, [sp, 8]	/* orig_r8 */
 	st      r0, [sp, 4]    /* orig_r0, needed only for sys calls */
 
 	/* Restore r9 used to code the early prologue */