iwlwifi: use bitfield.h for some registers

Letting the preprocessor/compiler generate the shift/mask by itself
is a win for readability, so use bitfield.h for some registers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 1da2de2..293f4b2 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -845,14 +845,14 @@ static void iwl_pcie_rx_mq_hw_init(struct iwl_trans *trans)
 	 * Set RX DMA chunk size to 64B for IOSF and 128B for PCIe
 	 * Default queue is 0
 	 */
-	iwl_write_prph_no_grab(trans, RFH_GEN_CFG, RFH_GEN_CFG_RFH_DMA_SNOOP |
-			       (DEFAULT_RXQ_NUM <<
-				RFH_GEN_CFG_DEFAULT_RXQ_NUM_POS) |
+	iwl_write_prph_no_grab(trans, RFH_GEN_CFG,
+			       RFH_GEN_CFG_RFH_DMA_SNOOP |
+			       RFH_GEN_CFG_VAL(DEFAULT_RXQ_NUM, 0) |
 			       RFH_GEN_CFG_SERVICE_DMA_SNOOP |
-			       (trans->cfg->integrated ?
-				RFH_GEN_CFG_RB_CHUNK_SIZE_64 :
-				RFH_GEN_CFG_RB_CHUNK_SIZE_128) <<
-			       RFH_GEN_CFG_RB_CHUNK_SIZE_POS);
+			       RFH_GEN_CFG_VAL(RB_CHUNK_SIZE,
+					       trans->cfg->integrated ?
+					       RFH_GEN_CFG_RB_CHUNK_SIZE_64 :
+					       RFH_GEN_CFG_RB_CHUNK_SIZE_128));
 	/* Enable the relevant rx queues */
 	iwl_write_prph_no_grab(trans, RFH_RXF_RXQ_ACTIVE, enabled);