arm: abb secu1: Convert CONFIG_BOOTDELAY to Kconfig

This converts the following to Kconfig:
   CONFIG_BOOTDELAY

Cc: Holger Brunck <holger.brunck@ch.abb.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/socfpga_arria5_secu1.h b/include/configs/socfpga_arria5_secu1.h
index 7791443..eb17470 100644
--- a/include/configs/socfpga_arria5_secu1.h
+++ b/include/configs/socfpga_arria5_secu1.h
@@ -28,7 +28,6 @@
 #define CONFIG_SYS_I2C_RTC_ADDR         0x68
 
 /* Booting Linux */
-#define CONFIG_BOOTDELAY	2
 #define CONFIG_BOOTFILE		"zImage"
 
 #define CONFIG_BOOTCOMMAND	\