iwlwifi: add inline helper for packet lengths

Add an inline helper function for getting an RX packet's
length or payload length and use it throughout the code
(most of which I did using an spatch.)

While at it, adjust some code, and remove a bogus comment
from the dvm calibration code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Eran Harary <eran.harary@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index 8d1b5ed..1f065cf 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -176,6 +176,16 @@
 	u8 data[];
 } __packed;
 
+static inline u32 iwl_rx_packet_len(const struct iwl_rx_packet *pkt)
+{
+	return le32_to_cpu(pkt->len_n_flags) & FH_RSCSR_FRAME_SIZE_MSK;
+}
+
+static inline u32 iwl_rx_packet_payload_len(const struct iwl_rx_packet *pkt)
+{
+	return iwl_rx_packet_len(pkt) - sizeof(pkt->hdr);
+}
+
 /**
  * enum CMD_MODE - how to send the host commands ?
  *