staging: rtl8192u: replace ternary statement with if and assignment

Replace ternary statement with an if statement followed by an assignment
to increase readability and make error handling more obvious.
Found with minmax coccinelle script.
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
Link: https://lore.kernel.org/r/36059ec66a2f3d58a8e339aa4f262772eabd3ef0.1649378587.git.remckee0@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c

@@ -470,7 +470,9 @@ int ieee80211_wx_get_encode(struct ieee80211_device *ieee,
 		return 0;
 	}
 	len = crypt->ops->get_key(keybuf, SCM_KEY_LEN, NULL, crypt->priv);
-	erq->length = (len >= 0 ? len : 0);
+	if (len < 0)
+		len = 0;
+	erq->length = len;
 
 	erq->flags |= IW_ENCODE_ENABLED;