Add a deprecation notice to remove RTE_ETH_DEV_DEFERRED state, but this
is mostly a reminder because of a missing target.
It doesn't worth to break the ABI because of this change and removal
can be done when ethdev ABI version increased.

Signed-off-by: Ferruh Yigit <redacted>
---
Cc: Thomas Monjalon <redacted>
Cc: Andrew Rybchenko <redacted>
Cc: Matan Azrad <redacted>
---
  doc/guides/rel_notes/deprecation.rst | 4 ++++
  1 file changed, 4 insertions(+)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index e2dbee317..9cd12ccd8 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst

@@ -95,3 +95,7 @@ Deprecation Notices
  
    This is due to a lack of flexibility and reliance on a type unusable with
    C++ programs (struct rte_flow_desc).
+
+* ethdev: remove deprecated RTE_ETH_DEV_DEFERRED device state.
+  Since this is an enum filed in the middle, removing this field will break
+  the ABI, so removing postponed to next ethdev ABI version increase.