staging: rtl8192u: replace macro rx_hal_is_cck_rate() in r8192U_core.c

This patch replaces macro rx_hal_is_cck_rate() with
the static inline function rx_hal_is_cck_rate().

This replacement was suggested by Dan Carpenter and
has the following benefits:
- improves code readability
- guarantees type safety
- improves code efficiency by enforcing the evaluation of
  the simple boolean expression (!pdrvinfo->RxHT) to be
  done before the evaluation of the more complex one
  (pdrvinfo->RxRate == DESC90_RATE1M ||
   pdrvinfo->RxRate == DESC90_RATE2M ||
   pdrvinfo->RxRate == DESC90_RATE5_5M ||
   pdrvinfo->RxRate == DESC90_RATE11M)

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8192U_core.c

@@ -236,12 +236,6 @@ static void rtl819x_set_channel_map(u8 channel_plan, struct r8192_priv *priv)
 }
 
 
-#define		rx_hal_is_cck_rate(_pdrvinfo)\
-			(_pdrvinfo->RxRate == DESC90_RATE1M ||\
-			_pdrvinfo->RxRate == DESC90_RATE2M ||\
-			_pdrvinfo->RxRate == DESC90_RATE5_5M ||\
-			_pdrvinfo->RxRate == DESC90_RATE11M) &&\
-			!_pdrvinfo->RxHT\
 
 
 void CamResetAllEntry(struct net_device *dev)
@@ -4228,6 +4222,22 @@ long rtl819x_signal_scale_mapping(long currsig)
 	return retsig;
 }
 
+static inline bool rx_hal_is_cck_rate(struct rx_drvinfo_819x_usb *pdrvinfo)
+{
+	if (pdrvinfo->RxHT)
+		return false;
+
+	switch (pdrvinfo->RxRate) {
+	case DESC90_RATE1M:
+	case DESC90_RATE2M:
+	case DESC90_RATE5_5M:
+	case DESC90_RATE11M:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static void rtl8192_query_rxphystatus(struct r8192_priv *priv,
 				      struct ieee80211_rx_stats *pstats,
 				      rx_drvinfo_819x_usb  *pdrvinfo,