JBD2/Ext4: Convert kmalloc to kzalloc in jbd2/ext4

Convert kmalloc to kzalloc() and get rid of the memset().

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index b10d68f..12c7d65 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -750,12 +750,11 @@
 		}
 	} else {
 		/* Allocate a buffer where we construct the new block. */
-		s->base = kmalloc(sb->s_blocksize, GFP_KERNEL);
+		s->base = kzalloc(sb->s_blocksize, GFP_KERNEL);
 		/* assert(header == s->base) */
 		error = -ENOMEM;
 		if (s->base == NULL)
 			goto cleanup;
-		memset(s->base, 0, sb->s_blocksize);
 		header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
 		header(s->base)->h_blocks = cpu_to_le32(1);
 		header(s->base)->h_refcount = cpu_to_le32(1);