MAINTAINERS: add include/acpi/ to ACPI

Add include/acpi/ to the realm of the ACPI maintainer.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 83fd68e..0462ade 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -55,6 +55,7 @@
 S:	Maintained
 F:	board/emulation/configs/acpi.config
 F:	cmd/acpi.c
+F:	include/acpi/
 F:	lib/acpi/
 
 ANDROID AB