doc: remove deprecation notices for eventdev

doc: remove deprecation notices for eventdev

All deprecation notice targeted for v21.11 of eventdev has been
committed in the following commits, remove deprecation notices.

Fixes: 3c838062b91 ("eventdev: introduce event vector Rx capability")
Fixes: 929ebdd5430 ("eventdev/eth_rx: simplify event vector config")
Fixes: 295c053f90f ("eventdev: hide event device related structures")
Fixes: dd451ad1520 ("doc: remove event crypto metadata deprecation note")
Reported-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Jerin Jacob <jerinj@marvell.com>