nios2: add gpio_is_valid

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>
diff --git a/board/altera/nios2-generic/custom_fpga.h b/board/altera/nios2-generic/custom_fpga.h
index a11add5..f7f3853 100644
--- a/board/altera/nios2-generic/custom_fpga.h
+++ b/board/altera/nios2-generic/custom_fpga.h
@@ -50,6 +50,7 @@
 
 /* led_pio.s1 is a altera_avalon_pio */
 #define LED_PIO_BASE 0x82120870
+#define LED_PIO_WIDTH 8
 
 /* high_res_timer.s1 is a altera_avalon_timer */
 #define CONFIG_SYS_TIMER_BASE 0x82120820