ata: pata_legacy: make legacy_exit() work again

Commit defc9cd8 ("pata_legacy: resychronize with upstream changes and
resubmit") missed to update legacy_exit(), so that it now fails to do any
cleanup -- the loop body there can never be entered.  Fix that and finally
remove now useless nr_legacy_host variable...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.

Fixes: defc9cd8 ("pata_legacy: resychronize with upstream changes and resubmit")
Cc: stable@vger.kernel.org
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

drivers/ata/pata_legacy.c

@@ -173,8 +173,6 @@ static int legacy_port[NR_HOST] = { 0x1f0, 0x170, 0x1e8, 0x168, 0x1e0, 0x160 };
 static struct legacy_probe probe_list[NR_HOST];
 static struct legacy_data legacy_data[NR_HOST];
 static struct ata_host *legacy_host[NR_HOST];
-static int nr_legacy_host;
-
 
 /**
  *	legacy_probe_add	-	Add interface to probe list
@@ -1276,9 +1274,11 @@ static __exit void legacy_exit(void)
 {
 	int i;
 
-	for (i = 0; i < nr_legacy_host; i++) {
+	for (i = 0; i < NR_HOST; i++) {
 		struct legacy_data *ld = &legacy_data[i];
-		ata_host_detach(legacy_host[i]);
+
+		if (legacy_host[i])
+			ata_host_detach(legacy_host[i]);
 		platform_device_unregister(ld->platform_dev);
 	}
 }