ethdev: add access to specific device info

ethdev: add access to specific device info

add new apis:
- rte_eth_dev_get_reg_length
- rte_eth_dev_get_reg_info
- rte_eth_dev_get_eeprom_length
- rte_eth_dev_get_eeprom
- rte_eth_dev_set_eeprom

to enable reading device parameters (register and
eeprom) based upon ethtool alike data parameter specification.

Signed-off-by: Liang-Min Larry Wang <liang-min.wang@intel.com>
Acked-by: Andrew Harvey <agh@cisco.com>
Acked-by: David Harton <dharton@cisco.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>