gpio: zynq: Fix typo in one error message

Just fix error message.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/gpio/zynq_gpio.c b/drivers/gpio/zynq_gpio.c
index afba458..9a91554 100644
--- a/drivers/gpio/zynq_gpio.c
+++ b/drivers/gpio/zynq_gpio.c
@@ -178,7 +178,7 @@
 	}
 
 	if (bank >= priv->p_data->max_bank) {
-		printf("Inavlid bank and pin num\n");
+		printf("Invalid bank and pin num\n");
 		*bank_num = 0;
 		*bank_pin_num = 0;
 	}