ethdev: prefix internal error checking macros

ethdev: prefix internal error checking macros

The macros to check that the function pointers and port ids are valid
for an ethdev are potentially useful to have in a common headers for
use with all PMDs. However, since they would then become externally
visible, we apply the RTE_ & RTE_ETH_ prefix to them as approtiate.

Signed-off-by: Declan Doherty <declan.doherty@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>