soc/amd/stoney: Don't use IS_ENABLED() for a constant

IS_ENABLED() was supposed for Kconfig options.

Change-Id: Ia40d64856cd89586133e54ff6e02c35d6b647059
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32225
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/stoneyridge/acpi/lpc.asl

@@ -13,7 +13,7 @@
  * GNU General Public License for more details.
  */
 
-#if IS_ENABLED(MAINBOARD_HAS_SPEAKER)
+#if MAINBOARD_HAS_SPEAKER
 #define IO61_HID "PNP0800" /* AT style speaker */
 #else
 #define IO61_HID "PNP0C02" /* reserved resource */