MAINTAINERS: Add maintainer for ACPI

Change-Id: I65fdee350273c58e027a002dba1f97a56115e195
Signed-off-by: Lance Zhao <lance.zhao@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48970
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Bora Guvendik <bora.guvendik@intel.com>
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
Reviewed-by: Maxim Polyakov <max.senia.poliak@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 49fbc38..7a82159 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -717,6 +717,8 @@
 F:	src/drivers/aspeed/ast2050/
 
 ACPI
+M:	Lance Zhao <lance.zhao@gmail.com>
+S:	Supported
 F:	src/acpi/
 F:	src/arch/x86/acpi/
 F:	util/acpi/