MIPS: xburst/start.S: use t8 register for dynamic relocation

Synchronize the code with mips{32,64}/start.S, in order to
allow further unifications.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>

arch/mips/cpu/xburst/start.S

@@ -117,19 +117,19 @@ in_ram:
 	 * generated by GNU ld. Skip these reserved entries from relocation.
 	 */
 	lw	t3, -4(t0)		# t3 <-- num_got_entries
-	lw	t4, -8(t0)		# t4 <-- _GLOBAL_OFFSET_TABLE_
-	add	t4, s1			# t4 now holds relocated _G_O_T_
-	addi	t4, t4, 8		# skipping first two entries
+	lw	t8, -8(t0)		# t8 <-- _GLOBAL_OFFSET_TABLE_
+	add	t8, s1			# t8 now holds relocated _G_O_T_
+	addi	t8, t8, 8		# skipping first two entries
 	li	t2, 2
 1:
-	lw	t1, 0(t4)
+	lw	t1, 0(t8)
 	beqz	t1, 2f
 	 add	t1, s1
-	sw	t1, 0(t4)
+	sw	t1, 0(t8)
 2:
 	addi	t2, 1
 	blt	t2, t3, 1b
-	 addi	t4, 4
+	 addi	t8, 4
 
 	/* Update dynamic relocations */
 	lw	t1, -16(t0)		# t1 <-- __rel_dyn_start
@@ -147,11 +147,11 @@ in_ram:
 
 	lw	t3, -8(t1)		# t3 <-- location to fix up in FLASH
 
-	lw	t4, 0(t3)		# t4 <-- original pointer
-	add	t4, s1			# t4 <-- adjusted pointer
+	lw	t8, 0(t3)		# t8 <-- original pointer
+	add	t8, s1			# t8 <-- adjusted pointer
 
 	add	t3, s1			# t3 <-- location to fix up in RAM
-	sw	t4, 0(t3)
+	sw	t8, 0(t3)
 
 2:
 	blt	t1, t2, 1b