ARC: entry: EV_Trap expects r10 (vs. r9) to have exception cause

avoids 1 MOV instruction in light of double load/store code
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/entry-arcv2.h

@@ -95,9 +95,8 @@
 	lr	r10, [ecr]
 	lr	r11, [erbta]
 	ST2	r10, r11, PT_event
-	mov	r9, r10
 
-	; OUTPUT: r9 has ECR
+	; OUTPUT: r10 has ECR expected by EV_Trap
 .endm
 
 /*------------------------------------------------------------------------

arch/arc/include/asm/entry-compact.h

@@ -195,8 +195,8 @@
 	PUSHAX  CTOP_AUX_EFLAGS
 #endif
 
-	lr	r9, [ecr]
-	st      r9, [sp, PT_event]    /* EV_Trap expects r9 to have ECR */
+	lr	r10, [ecr]
+	st      r10, [sp, PT_event]    /* EV_Trap expects r10 to have ECR */
 .endm
 
 /*--------------------------------------------------------------

arch/arc/kernel/entry-compact.S

@@ -256,7 +256,7 @@ ENTRY(EV_TLBProtV)
 
 	EXCEPTION_PROLOGUE
 
-	mov r2, r9	; ECR set into r9 already
+	mov r2, r10	; ECR set into r10 already
 	lr  r0, [efa]	; Faulting Data address (not part of pt_regs saved above)
 
 	; Exception auto-disables further Intr/exceptions.

arch/arc/kernel/entry.S

@@ -232,8 +232,8 @@ ENTRY(EV_Trap)
 	EXCEPTION_PROLOGUE
 
 	;============ TRAP 1   :breakpoints
-	; Check ECR for trap with arg (PROLOGUE ensures r9 has ECR)
-	bmsk.f 0, r9, 7
+	; Check ECR for trap with arg (PROLOGUE ensures r10 has ECR)
+	bmsk.f 0, r10, 7
 	bnz    trap_with_param
 
 	;============ TRAP  (no param): syscall top level