Ported the gigabit transceiver from tr_nonbonded phy_gx.vhd to tech_transceiver_gx_stratixiv.vhd.

The tech_transceiver_gx_stratixiv.vhd is instantiated in tech_transceiver_gx.vhd when g_technology=c_tech_stratixiv.
The tech_transceiver_gx.vhd is the technology independent component for the user.