x86: Tidy up use of CONFIG_ACPIGEN

This is enabled for quite a few boards which don't create ACPI tables.
Tidy this up by dropping the option for some boards.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/cherryhill_defconfig b/configs/cherryhill_defconfig
index 73120b5..7bfbcf6 100644
--- a/configs/cherryhill_defconfig
+++ b/configs/cherryhill_defconfig
@@ -40,6 +40,7 @@
 CONFIG_TFTP_TSIZE=y
 CONFIG_REGMAP=y
 CONFIG_SYSCON=y
+# CONFIG_ACPIGEN is not set
 CONFIG_CPU=y
 CONFIG_RTL8169=y
 CONFIG_SPI=y