drivers/mtd: Use kzalloc

Use kzalloc rather than the combination of kmalloc and memset.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,size,flags;
statement S;
@@

-x = kmalloc(size,flags);
+x = kzalloc(size,flags);
 if (x == NULL) S
-memset(x, 0, size);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/tests/mtd_readtest.c

@@ -141,12 +141,11 @@ static int scan_for_bad_eraseblocks(void)
 {
 	int i, bad = 0;
 
-	bbt = kmalloc(ebcnt, GFP_KERNEL);
+	bbt = kzalloc(ebcnt, GFP_KERNEL);
 	if (!bbt) {
 		printk(PRINT_PREF "error: cannot allocate memory\n");
 		return -ENOMEM;
 	}
-	memset(bbt, 0 , ebcnt);
 
 	/* NOR flash does not implement block_isbad */
 	if (mtd->block_isbad == NULL)