app: fix usage help of options separated by dashes

app: fix usage help of options separated by dashes

The EAL options and app-specific options are separated
with double dashes.

The help of testpmd, test-acl and pdump were missing
the dashes after EAL options.
Note: testpmd was completely missing the EAL options.

Fixes: af75078fece3 ("first public release")
Fixes: 26c057ab6c45 ("acl: new test-acl application")
Fixes: b2854d5317e8 ("app/pdump: support multi-core capture")
Cc: stable@dpdk.org
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>