ath10k: pci: remove unnecessary casts

Fixes checkpatch warnings:

drivers/net/wireless/ath/ath10k/pci.c:926: unnecessary cast may hide bugs, see http://c-faq.com/malloc/mallocnocast.html
drivers/net/wireless/ath/ath10k/pci.c:1072: unnecessary cast may hide bugs, see http://c-faq.com/malloc/mallocnocast.html

While at it, also remove unnecessary initialisation of data_buf variable in both cases.

Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath10k/pci.c

@@ -909,7 +909,7 @@ static int ath10k_pci_diag_read_mem(struct ath10k *ar, u32 address, void *data,
 	/* Host buffer address in CE space */
 	u32 ce_data;
 	dma_addr_t ce_data_base = 0;
-	void *data_buf = NULL;
+	void *data_buf;
 	int i;
 
 	mutex_lock(&ar_pci->ce_diag_mutex);
@@ -923,10 +923,8 @@ static int ath10k_pci_diag_read_mem(struct ath10k *ar, u32 address, void *data,
 	 */
 	alloc_nbytes = min_t(unsigned int, nbytes, DIAG_TRANSFER_LIMIT);
 
-	data_buf = (unsigned char *)dma_alloc_coherent(ar->dev, alloc_nbytes,
-						       &ce_data_base,
-						       GFP_ATOMIC);
-
+	data_buf = dma_alloc_coherent(ar->dev, alloc_nbytes, &ce_data_base,
+				      GFP_ATOMIC);
 	if (!data_buf) {
 		ret = -ENOMEM;
 		goto done;
@@ -1054,7 +1052,7 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 address,
 	u32 *buf;
 	unsigned int completed_nbytes, alloc_nbytes, remaining_bytes;
 	struct ath10k_ce_pipe *ce_diag;
-	void *data_buf = NULL;
+	void *data_buf;
 	dma_addr_t ce_data_base = 0;
 	int i;
 
@@ -1069,10 +1067,8 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 address,
 	 */
 	alloc_nbytes = min_t(unsigned int, nbytes, DIAG_TRANSFER_LIMIT);
 
-	data_buf = (unsigned char *)dma_alloc_coherent(ar->dev,
-						       alloc_nbytes,
-						       &ce_data_base,
-						       GFP_ATOMIC);
+	data_buf = dma_alloc_coherent(ar->dev, alloc_nbytes, &ce_data_base,
+				      GFP_ATOMIC);
 	if (!data_buf) {
 		ret = -ENOMEM;
 		goto done;