MAINTAINERS: Cover qapi/cxl.json

Commit 415442a1b4a (hw/mem/cxl_type3: Add CXL RAS Error Injection
Support.) created qapi/cxl.json without adding it to MAINTAINERS.  Fix
that.

Cc: Ben Widawsky <ben.widawsky@intel.com>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240205084747.3623569-2-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 2f9741b..00ada76 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2894,6 +2894,7 @@
 F: hw/cxl/
 F: hw/mem/cxl_type3.c
 F: include/hw/cxl/
+F: qapi/cxl.json
 
 Dirty Bitmaps
 M: Eric Blake <eblake@redhat.com>