enic: fix warnings

enic: fix warnings

A lot of warnings were not seen because $(WERROR_FLAGS) was not set
in the Makefile. But they appear with toolchains that enforce more checks.

-Wno-deprecated seems useless.
-Wno-strict-aliasing is added to avoid false positives.

This patch cleans up unused variable, unused functions, wrong types,
static declarations, etc. A lot of functions have unused parameters;
it suggests that more clean-up could be needed.

Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>
Acked-by: Sujith Sankar <ssujith@cisco.com>