meson.build: add missing MCTP schema

Add the missing MCTP schema.

Related PRs:
https://gerrit.openbmc.org/c/openbmc/entity-manager/+/69600
https://gerrit.openbmc.org/c/openbmc/entity-manager/+/76412

Change-Id: I57f9e949ae83f68aee85fe793a5e1459954e590f
Signed-off-by: Yikai Tsai <yikai.tsai.wiwynn@gmail.com>
diff --git a/meson.build b/meson.build
index ceba0ef..b704687 100644
--- a/meson.build
+++ b/meson.build
@@ -108,6 +108,7 @@
     'openbmc-dbus.json',
     'ibm.json',
     'intel.json',
+    'mctp.json',
     'pid.json',
     'pid_zone.json',
     'stepwise.json',