staging: rtl8192e: Prefer using macro DIV_ROUND_UP

The macro DIV_ROUND_UP performs the computation
(((n) + (d) - 1) /(d)). It clarifies the divisor calculations.
This was done using the coccinelle script:
@@
expression e1;
expression e2;
@@
(
- ((e1) + e2 - 1) / (e2)
+ DIV_ROUND_UP(e1,e2)
|
- ((e1) + (e2 - 1)) / (e2)
+ DIV_ROUND_UP(e1,e2)
)

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtllib_crypt_ccmp.c

@@ -233,7 +233,7 @@ static int rtllib_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 		ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len,
 				 b0, b, s0);
 
-		blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
+		blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
 		last = data_len % AES_BLOCK_LEN;
 
 		for (i = 1; i <= blocks; i++) {
@@ -319,7 +319,7 @@ static int rtllib_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 		ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 		xor_block(mic, b, CCMP_MIC_LEN);
 
-		blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
+		blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
 		last = data_len % AES_BLOCK_LEN;
 
 		for (i = 1; i <= blocks; i++) {