i40e/base: add new interfaces

i40e/base: add new interfaces

Four new interfaces are added for future use, as follows, together
with their relevant strucure and macro definitions.
- i40e_aq_read_nvm_config()
- i40e_aq_write_nvm_config()
- i40e_aq_set_lldp_mib()
- i40e_read_pba_string()
In addition, removed i40e_read_nvm_srrd() as needed.

Test report: http://www.dpdk.org/ml/archives/dev/2015-May/017384.html

Signed-off-by: Helin Zhang <helin.zhang@intel.com>
Acked-by: Jijiang Liu <jijiang.liu@intel.com>
Tested-by: Min Cao <min.cao@intel.com>