doc: fix description of links to EAL options pages

doc: fix description of links to EAL options pages

Documentation includes separate pages of EAL command-line options for
Linux and for FreeBSD.
Links to these pages use the same text 'EAL parameters', so it is not
clear which link to use for which environment.

This patch adds the text '(Linux)' and '(FreeBSD)' where relevant, to
clearly identify the links.

Fixes: 3ee567cfec37 ("doc: document all EAL parameters in one place")
Cc: stable@dpdk.org
Signed-off-by: Dekel Peled <dekelp@mellanox.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>