enic: fix build by using standard integer types

enic: fix build by using standard integer types

ENIC PMD was giving compilation errors on ppc_64-power8-linuxapp-gcc because
of types such as u_int32_t.  This patch replaces all those with uint32_t and
similar ones.

Reported-by: David Marchand <david.marchand@6wind.com>
Signed-off-by: Sujith Sankar <ssujith@cisco.com>
Acked-by: David Marchand <david.marchand@6wind.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>