Bluetooth: btintel_pcie: Remove unnecessary memset(0) calls

Remove memset(0) after dma_alloc_coherent(), which already zeroes out
the memory, and fix the following two Coccinelle/coccicheck warnings
reported by zalloc-simple.cocci:

btintel_pcie.c:837:19-37: WARNING: dma_alloc_coherent used in

	/* Allocate full chunk of data buffer for DMA first and do indexing and
	 * initialization next, so it can be freed easily
	 */
	rxq->buf_v_addr   already zeroes out memory, so memset is not needed

btintel_pcie.c:792:19-37: WARNING: dma_alloc_coherent used in

	/* Allocate full chunk of data buffer for DMA first and do indexing and
	 * initialization next, so it can be freed easily
	 */
	txq->buf_v_addr   already zeroes out memory, so memset is not needed

Fixes: c2b636b3 ("Bluetooth: btintel_pcie: Add support for PCIe transport")
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>