dm crypt: Fix sparse complaints

Avoid that sparse complains about assigning a __le64 value to a u64
variable.  Remove the (u64) casts since these are superfluous.  This
patch does not change the behavior of the source code.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 96dd5d7..8f2e3e2 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -683,7 +683,7 @@
 				  u8 *data)
 {
 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
-	u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
+	__le64 sector = cpu_to_le64(dmreq->iv_sector);
 	u8 buf[TCW_WHITENING_SIZE];
 	SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm);
 	int i, r;
@@ -722,7 +722,7 @@
 			    struct dm_crypt_request *dmreq)
 {
 	struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw;
-	u64 sector = cpu_to_le64((u64)dmreq->iv_sector);
+	__le64 sector = cpu_to_le64(dmreq->iv_sector);
 	u8 *src;
 	int r = 0;