staging/rtl8192e: avoid comparing unsigned type >= 0

There is one remaining warning about a type limit check in rtl8192e:

staging/rtl8192e/rtl819x_TSProc.c:326:14: error: comparison is always true due to limited range of data type [-Werror=type-limits]

This changes a macro into a local function to clarify the types and simplify
the check while removing the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtl819x_Qos.h

@@ -169,9 +169,6 @@ union qos_tclas {
 	} TYPE2_8021Q;
 };
 
-#define IsACValid(ac)		((ac >= 0 && ac <= 7) ? true : false)
-
-
 union aci_aifsn {
 	u8	charData;
 

drivers/staging/rtl8192e/rtl819x_TSProc.c

@@ -306,6 +306,11 @@ static void MakeTSEntry(struct ts_common_info *pTsCommonInfo, u8 *Addr,
 	pTsCommonInfo->TClasNum = TCLAS_Num;
 }
 
+static bool IsACValid(unsigned int tid)
+{
+	return tid < 7;
+}
+
 bool GetTs(struct rtllib_device *ieee, struct ts_common_info **ppTS,
 	   u8 *Addr, u8 TID, enum tr_select TxRxSelect, bool bAddNewTs)
 {