xtensa: reorganize SR referencing

- reference SRs by names where possible, not by numbers;
- get rid of __stringify around SR names where possible;
- remove unneeded SR names from asm/regs.h;
- add SREG_ prefix to remaining SR names;

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/kernel/align.S b/arch/xtensa/kernel/align.S
index 33d6e9d..934ae58 100644
--- a/arch/xtensa/kernel/align.S
+++ b/arch/xtensa/kernel/align.S
@@ -170,15 +170,15 @@
 	s32i	a7, a2, PT_AREG7
 	s32i	a8, a2, PT_AREG8
 
-	rsr	a0, DEPC
-	xsr	a3, EXCSAVE_1
+	rsr	a0, depc
+	xsr	a3, excsave1
 	s32i	a0, a2, PT_AREG2
 	s32i	a3, a2, PT_AREG3
 
 	/* Keep value of SAR in a0 */
 
-	rsr	a0, SAR
-	rsr	a8, EXCVADDR		# load unaligned memory address
+	rsr	a0, sar
+	rsr	a8, excvaddr		# load unaligned memory address
 
 	/* Now, identify one of the following load/store instructions.
 	 *
@@ -197,7 +197,7 @@
 
 	/* Extract the instruction that caused the unaligned access. */
 
-	rsr	a7, EPC_1	# load exception address
+	rsr	a7, epc1	# load exception address
 	movi	a3, ~3
 	and	a3, a3, a7	# mask lower bits
 
@@ -275,16 +275,16 @@
 1:
 
 #if XCHAL_HAVE_LOOPS
-	rsr	a5, LEND		# check if we reached LEND
+	rsr	a5, lend		# check if we reached LEND
 	bne	a7, a5, 1f
-	rsr	a5, LCOUNT		# and LCOUNT != 0
+	rsr	a5, lcount		# and LCOUNT != 0
 	beqz	a5, 1f
 	addi	a5, a5, -1		# decrement LCOUNT and set
-	rsr	a7, LBEG		# set PC to LBEGIN
-	wsr	a5, LCOUNT
+	rsr	a7, lbeg		# set PC to LBEGIN
+	wsr	a5, lcount
 #endif
 
-1:	wsr	a7, EPC_1		# skip load instruction
+1:	wsr	a7, epc1		# skip load instruction
 	extui	a4, a4, INSN_T, 4	# extract target register
 	movi	a5, .Lload_table
 	addx8	a4, a4, a5
@@ -355,16 +355,16 @@
 
 1:
 #if XCHAL_HAVE_LOOPS
-	rsr	a4, LEND		# check if we reached LEND
+	rsr	a4, lend		# check if we reached LEND
 	bne	a7, a4, 1f
-	rsr	a4, LCOUNT		# and LCOUNT != 0
+	rsr	a4, lcount		# and LCOUNT != 0
 	beqz	a4, 1f
 	addi	a4, a4, -1		# decrement LCOUNT and set
-	rsr	a7, LBEG		# set PC to LBEGIN
-	wsr	a4, LCOUNT
+	rsr	a7, lbeg		# set PC to LBEGIN
+	wsr	a4, lcount
 #endif
 
-1:	wsr	a7, EPC_1		# skip store instruction
+1:	wsr	a7, epc1		# skip store instruction
 	movi	a4, ~3
 	and	a4, a4, a8		# align memory address
 
@@ -406,7 +406,7 @@
 
 .Lexit:
 	movi	a4, 0
-	rsr	a3, EXCSAVE_1
+	rsr	a3, excsave1
 	s32i	a4, a3, EXC_TABLE_FIXUP
 
 	/* Restore working register */
@@ -420,7 +420,7 @@
 
 	/* restore SAR and return */
 
-	wsr	a0, SAR
+	wsr	a0, sar
 	l32i	a0, a2, PT_AREG0
 	l32i	a2, a2, PT_AREG2
 	rfe
@@ -438,10 +438,10 @@
 	l32i	a6, a2, PT_AREG6
 	l32i	a5, a2, PT_AREG5
 	l32i	a4, a2, PT_AREG4
-	wsr	a0, SAR
+	wsr	a0, sar
 	mov	a1, a2
 
-	rsr	a0, PS
+	rsr	a0, ps
         bbsi.l  a2, PS_UM_BIT, 1f     # jump if user mode
 
 	movi	a0, _kernel_exception