gpio presence: configuration schema

Add the configuration schema as per the design [1].

References:

[1] https://github.com/openbmc/docs/blob/master/designs/inventory/gpio-based-hardware-inventory.md

Change-Id: I1ee3d75bf1c2f5ba470293505bea46c840344fc8
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/meson.build b/meson.build
index 58433bb..a63b6a9 100644
--- a/meson.build
+++ b/meson.build
@@ -91,6 +91,7 @@
 schemas = [
     'cpld.json',
     'global.json',
+    'gpio_presence.json',
     'legacy.json',
     'openbmc-dbus.json',
     'ibm.json',