Revert "Revert "[mstlink] Fixing lane width for 50G PAM4""

Author: Mustafa J. Dalloul

mlxlink/modules/mlxlink_maps.cpp

@@ -396,6 +396,7 @@ MlxlinkMaps::MlxlinkMaps() {
     _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_XLAUI_4] = 4;
     _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_25GAUI_1] = 1;
     _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_50GAUI_2] = 2;
+    _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_50GAUI_1] = 1;
     _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_CAUI_4] = 4;
     _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_100GAUI_2] = 2;
     _ExtETHSpeed2Lanes[ETH_LINK_SPEED_EXT_200GAUI_4] = 4;