doc: fix wrong usage of bind command
doc: fix wrong usage of bind command

This patch fixes wrong usage of bind command in vhost.rst.
Using "dpdk-devbind.py -b=uio_pci_generic 0000:00:04.0" gives
an error of "unbind failed". It should be "-b uio_pci_generic" so
it will work correctly.

Fixes: a971c509a523 ("doc: update vhost sample guide")
Cc: stable@dpdk.org

Signed-off-by: Rami Rosen <d906574dd7f018d5d95e7b7a8107cdf708745f05@gmail.com>
Acked-by: Zhiyong Yang <fbdb847fac8e5e50b588eb93d9ff9fd811b7568c@intel.com>
Reviewed-by: Maxime Coquelin <9a2667dee3b90866bbc9c2696cff2b7d5616c95a@redhat.com>

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