Change #ifdef and #if defined CONFIG_ bools to #if IS_ENABLED()

Kconfigs symbols of type bool are always defined, and can be tested with
the IS_ENABLED() macro.

symbol type except string.

Change-Id: Ic4ba79f519ee2a53d39c10859bbfa9c32015b19d
Signed-off-by: Martin Roth <gaumless@gmail.com>
Reviewed-on: http://review.coreboot.org/10885
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/arch/riscv/bootblock_simple.c

@@ -56,7 +56,7 @@ void main(void)
 		//bootblock_mainboard_init();
 	}
 
-#ifdef CONFIG_BOOTBLOCK_CONSOLE
+#if IS_ENABLED(CONFIG_BOOTBLOCK_CONSOLE)
 	console_init();
 	exception_init();
 #endif