ethdev: rename map file to match library name

ethdev: rename map file to match library name

While almost all libraries have the library name match the directory name,
some libraries and drivers do not. For those that don't, some have the
version filename use the libname, e.g. null_crypto, others have it use the
directory name, e.g. ether. Using the library name seems the better
standard to follow, so rename rte_ether_version.map to
rte_ethdev_version.map.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>