qapi: Extract ACPI commands to 'acpi.json'

Only qemu-system-FOO and qemu-storage-daemon provide QMP
monitors, therefore such declarations and definitions are
irrelevant for user-mode emulation.

Extracting the ACPI commands to their own schema reduces the size of
the qapi-misc* headers generated, and pulls less QAPI-generated code
into user-mode.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200913195348.1064154-8-philmd@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 5eed1e6..f99b5db 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1632,6 +1632,7 @@
 F: hw/smbios/*
 F: hw/i386/acpi-build.[hc]
 F: hw/arm/virt-acpi-build.c
+F: qapi/acpi.json
 F: tests/qtest/bios-tables-test*
 F: tests/qtest/acpi-utils.[hc]
 F: tests/data/acpi/