hci: llc_shdlc: style: Simplify bool comparison

Fix the following coccicheck warning:
./net/nfc/hci/llc_shdlc.c:239:5-21: WARNING: Comparison to bool

Signed-off-by: YANG LI <abaci-bugfix@linux.alibaba.com>
Reported-by: Abaci Robot<abaci@linux.alibaba.com>
Link: https://lore.kernel.org/r/1610357063-57705-1-git-send-email-abaci-bugfix@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/nfc/hci/llc_shdlc.c

@@ -236,7 +236,7 @@ static void llc_shdlc_rcv_i_frame(struct llc_shdlc *shdlc,
 		goto exit;
 	}
 
-	if (shdlc->t1_active == false) {
+	if (!shdlc->t1_active) {
 		shdlc->t1_active = true;
 		mod_timer(&shdlc->t1_timer, jiffies +
 			  msecs_to_jiffies(SHDLC_T1_VALUE_MS(shdlc->w)));