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>
diff --git a/drivers/gpio/mcp23s08.c b/drivers/gpio/mcp23s08.c
index 7fb5b9d..7f92fdd 100644
--- a/drivers/gpio/mcp23s08.c
+++ b/drivers/gpio/mcp23s08.c
@@ -168,7 +168,7 @@
 {
 	struct mcp23s08	*mcp;
 	char		bank;
-	unsigned	t;
+	int		t;
 	unsigned	mask;
 
 	mcp = container_of(chip, struct mcp23s08, chip);