staging: vt6655: replace NULL comparison with variable

Replace NULL comparison of the variable with just the variable name to
conform to the Linux kernel coding style. Issue found using checkpatch.
Signed-off-by: Santha Meena Ramamoorthy <santhameena13@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/rxtx.c

@@ -966,7 +966,7 @@ s_vGenerateTxParameter(
 		return;
 
 	if (byPktType == PK_TYPE_11GB || byPktType == PK_TYPE_11GA) {
-		if (pvRTS != NULL) { /* RTS_need */
+		if (pvRTS) { /* RTS_need */
 			/* Fill RsvTime */
 			struct vnt_rrv_time_rts *buf = pvRrvTime;
 
@@ -988,7 +988,7 @@ s_vGenerateTxParameter(
 			s_vFillCTSHead(pDevice, uDMAIdx, byPktType, pvCTS, cbFrameSize, bNeedACK, bDisCRC, wCurrentRate, byFBOption);
 		}
 	} else if (byPktType == PK_TYPE_11A) {
-		if (pvRTS != NULL) {/* RTS_need, non PCF mode */
+		if (pvRTS) {/* RTS_need, non PCF mode */
 			struct vnt_rrv_time_ab *buf = pvRrvTime;
 
 			buf->rts_rrv_time = s_uGetRTSCTSRsvTime(pDevice, 2, byPktType, cbFrameSize, wCurrentRate);
@@ -1002,7 +1002,7 @@ s_vGenerateTxParameter(
 			buf->rrv_time = vnt_rxtx_rsvtime_le16(pDevice, PK_TYPE_11A, cbFrameSize, wCurrentRate, bNeedACK);
 		}
 	} else if (byPktType == PK_TYPE_11B) {
-		if (pvRTS != NULL) {/* RTS_need, non PCF mode */
+		if (pvRTS) {/* RTS_need, non PCF mode */
 			struct vnt_rrv_time_ab *buf = pvRrvTime;
 
 			buf->rts_rrv_time = s_uGetRTSCTSRsvTime(pDevice, 0, byPktType, cbFrameSize, wCurrentRate);