Reorganise and improve comments for ignored ABI changes

debian/changelog

@@ -210,7 +210,7 @@ linux (4.9.15-1) UNRELEASED; urgency=medium
   * [rt] Update to 4.9.13-rt12:
     - timer/hrtimer: check properly for a running timer
   * [rt] Refresh one patch that had a textual conflict with 4.9.14
-  * Ignore ABI changes in rds and ufshcd, not useful to OOT modules
+  * Ignore various ABI changes that shouldn't affect OOT modules
   * ucount: Remove the atomicity from ucount->count (CVE-2017-6874)
   * userns: Avoid ABI change for CVE-2017-6874 fix
   * [amd64] Don't WARN about expected W+X pages on Xen (see #852324)

debian/config/defines

@@ -5,8 +5,10 @@ ignore-changes:
  module:drivers/hv/*
  module:drivers/iio/common/st_sensors/**
  module:drivers/net/wireless/**
+ module:drivers/nvdimm/libnvdimm
  module:drivers/power/supply/bq27xxx_battery
  module:drivers/scsi/ufs/*
+ module:drivers/target/**
  module:drivers/usb/host/**
  module:drivers/usb/musb/**
  module:net/ceph/libceph
@@ -23,14 +25,11 @@ ignore-changes:
  update_devfreq
 # Assume IB drivers are added/updated through OFED, which also updates IB core
  module:drivers/infiniband/**
-# ignore acpi_ec_{add,remove}_query_handler(), not exposed for OOT modules
+# Declared in private header, not usable OOT
  acpi_ec_add_query_handler
  acpi_ec_remove_query_handler
-# not declared in a public header
  first_ec
-# Ignore some ABI changes from 4.9.15 import
- module:drivers/nvdimm/libnvdimm
- module:drivers/target/**
+# Exported for tracefs only
  debugfs_create_automount
 
 [base]