netfilter: Remove unnecessary conversion to bool

Here we could use the '!=' expression to fix the following coccicheck
warning:

./net/netfilter/xt_nfacct.c:30:41-46: WARNING: conversion to bool not needed here

Reported-by: Tosk Robot <[e-mail]>
Signed-off-by: Kaixu Xia <[e-mail]>
Signed-off-by: Pablo Neira Ayuso <[e-mail]>

net/netfilter/xt_nfacct.c

···
 
 	overquota = nfnl_acct_overquota(xt_net(par), info->nfacct);
 
-	return overquota == NFACCT_UNDERQUOTA ? false : true;
+	return overquota != NFACCT_UNDERQUOTA;
 }
 
 static int