doc: fix crypto scheduler command line examples

Sample command lines for crypto scheduler were not correct,
due to:
- Typo in "crypto_scheduler" driver name
- Multiple virtual devices require having unique names,
  driver name + a suffix, otherwise, just a single device is
  created.

Fixes: d58a3f312545 ("crypto/scheduler: add documentation")
Cc: stable@dpdk.org
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>