mb/facebook/watson: Don't use deprecated IS_ENABLED

Change-Id: Ia4b7311f30f8ec951d02d3c31c30cf8895ed0eb2
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32312
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/mainboard/facebook/watson/mainboard.c

@@ -29,7 +29,7 @@ static void mainboard_enable(struct device *dev)
 
 static void mainboard_init(void *chip_info)
 {
-#if !IS_ENABLED(CONFIG_ENABLE_TURBO)
+#if !CONFIG(ENABLE_TURBO)
 	disable_turbo();
 #endif
 }