mtd: mtdswap: make array 'name' static const, shrinks object size

Don't populate the read-only array 'name' on the stack but instead
make it static and constify it. Makes the object code smaller by 35
bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
  26304	   4444	    352	  31100	   797c	drivers/mtd/mtdswap.o

After:
   text	   data	    bss	    dec	    hex	filename
  26205	   4508	    352	  31065	   7959	drivers/mtd/mtdswap.o

(gcc version 7.2.0 x86_64)
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/mtdswap.c

@@ -1223,8 +1223,9 @@ static int mtdswap_show(struct seq_file *s, void *data)
 	unsigned int max[MTDSWAP_TREE_CNT];
 	unsigned int i, cw = 0, cwp = 0, cwecount = 0, bb_cnt, mapped, pages;
 	uint64_t use_size;
-	char *name[] = {"clean", "used", "low", "high", "dirty", "bitflip",
-			"failing"};
+	static const char * const name[] = {
+		"clean", "used", "low", "high", "dirty", "bitflip", "failing"
+	};
 
 	mutex_lock(&d->mbd_dev->lock);