gpio: mcp23s08 debug fix

The return value of mcp23s08_read_regs() can only be evaluated when signed
Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/mcp23s08.c

@@ -168,7 +168,7 @@ static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 {
 	struct mcp23s08	*mcp;
 	char		bank;
-	unsigned	t;
+	int		t;
 	unsigned	mask;
 
 	mcp = container_of(chip, struct mcp23s08, chip);