doc: remove unneeded deprecation notice
doc: remove unneeded deprecation notice

In release 18.05, a deprecation notice to remove the `sym`
structure in the cryptodev info structure was sent.
However, only one of the fields inside the structure will
be removed, so the notice is not actually correct.
In any case, it needs to be removed.

Signed-off-by: Pablo de Lara <28355d9cfe41bb8148aea0fb24f47aae8f4217a1@intel.com>
Acked-by: Akhil Goyal <74d7c4c993a22c1d4f60c46ff3d95c969a24a25c@nxp.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk