[PATCH v2] doc: add event timer expiry drop stat

[Naga Harish K S V <s.v.naga.harish.k@intel.com>]

The structure ``rte_event_timer_adapter_stats`` will be
extended by adding a new field, ``evtim_drop_count``. This stat
will represent the number of times an event_timer expiry event
is dropped by the event timer adapter.

Signed-off-by: Naga Harish K S V <s.v.naga.harish.k@intel.com>
---
v2:
* update commit message
---
 doc/guides/rel_notes/deprecation.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 4e5b23c53d..597a457a37 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -125,3 +125,9 @@ Deprecation Notices
   applications should be updated to use the ``dmadev`` library instead,
   with the underlying HW-functionality being provided by the ``ioat`` or
   ``idxd`` dma drivers
+
+* eventdev/timer: The structure ``rte_event_timer_adapter_stats`` will be
+  extended by adding a new field, ``evtim_drop_count``. This stat will
+  represent the number of times an event_timer expiry event is dropped
+  by the timer adapter. This field will be used by a future patch adding
+  support for periodic mode to the software timer adapter in DPDK 22.11.
-- 
2.25.1