Blackfin arch: As Mike pointed out range goes form m..MAX_BLACKFIN_GPIO -1

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/arch/blackfin/kernel/bfin_gpio.c b/arch/blackfin/kernel/bfin_gpio.c
index 3f49fae..8cefed8 100644
--- a/arch/blackfin/kernel/bfin_gpio.c
+++ b/arch/blackfin/kernel/bfin_gpio.c
@@ -138,7 +138,7 @@
 
 inline int check_gpio(unsigned short gpio)
 {
-	if (gpio > MAX_BLACKFIN_GPIOS)
+	if (gpio >= MAX_BLACKFIN_GPIOS)
 		return -EINVAL;
 	return 0;
 }