Avoid flushing the same line multiple times on loongson.

* grub-core/kern/mips/cache.S [GRUB_MACHINE_MIPS_LOONGSON]:
	Step in 32 bytes and not 1 byte.
	* grub-core/kern/mips/cache_flush.S [GRUB_MACHINE_MIPS_LOONGSON]:
	Likewise.

grub-core/kern/mips/cache.S

@@ -21,25 +21,49 @@ FUNCTION (grub_arch_sync_dma_caches)
 	subu $t1, $t3, $t2
 1:
 	cache 1, 0($t0)
-	addiu $t1, $t1, 0xffff
+#ifdef GRUB_MACHINE_MIPS_LOONGSON
+	cache 1, 1($t0)
+	cache 1, 2($t0)
+	cache 1, 3($t0)
+
+	addiu $t1, $t1, -0x20
 	bne $t1, $zero, 1b
-	 addiu $t0, $t0, 0x1
+	 addiu $t0, $t0, 0x20
+#else
+	addiu $t1, $t1, -4
+	bne $t1, $zero, 1b
+	 addiu $t0, $t0, 0x4
+#endif
 	sync
 	move $t0, $t2
 	subu $t1, $t3, $t2
 2:
+#ifdef GRUB_MACHINE_MIPS_LOONGSON
 	cache 0, 0($t0)
-	addiu $t1, $t1, 0xffff
+	addiu $t1, $t1, -0x20
 	bne $t1, $zero, 2b
-	 addiu $t0, $t0, 0x1
+	 addiu $t0, $t0, 0x20
+#else
+	cache 0, 0($t0)
+	addiu $t1, $t1, -4
+	bne $t1, $zero, 2b
+	 addiu $t0, $t0, 0x4
+#endif
 	sync
 	move $t0, $t2
 	subu $t1, $t3, $t2
 2:
+#ifdef GRUB_MACHINE_MIPS_LOONGSON
 	cache 23, 0($t0)
-	addiu $t1, $t1, 0xffff
+	addiu $t1, $t1, -0x20
 	bne $t1, $zero, 2b
-	 addiu $t0, $t0, 0x1
+	 addiu $t0, $t0, 0x20
+#else
+	cache 23, 0($t0)
+	addiu $t1, $t1, -0x4
+	bne $t1, $zero, 2b
+	 addiu $t0, $t0, 0x4
+#endif
 	sync
 
 	jr $ra

grub-core/kern/mips/cache_flush.S

@@ -14,17 +14,27 @@
 	cache 1, 1($t0)
 	cache 1, 2($t0)
 	cache 1, 3($t0)
-#endif
+	addiu $t1, $t1, -0x20
+	bne $t1, $zero, 1b
+	 addiu $t0, $t0, 0x20
 
+#else
 	addiu $t1, $t1, -0x4
 	bne $t1, $zero, 1b
 	 addiu $t0, $t0, 0x4
+#endif
 	sync
 	move $t0, $t2
 	subu $t1, $t3, $t2
 2:
 	cache 0, 0($t0)
+#ifdef GRUB_MACHINE_MIPS_LOONGSON
+	addiu $t1, $t1, -0x20
+	bne $t1, $zero, 2b
+	 addiu $t0, $t0, 0x20
+#else
 	addiu $t1, $t1, -0x4
 	bne $t1, $zero, 2b
 	 addiu $t0, $t0, 0x4
+#endif
 	sync