[201811][sonic-config-engine] Parse AutoNegotiation element from LinkMetadata section of minigraph file (#7048)

Backport of #7031 to the 201811 branch

#### Why I did it

To enable parsing the `AutoNegotiation` element from the LinkMetadata section of minigraph file

#### How I did it

Parse the value `AutoNegotiation` element from the `LinkMetadata` section of minigraph file. If the element is present, an `autoneg` key will be added to the port in the `PORT` table of Config DB with a value of either `0` or `1`

If an `autoneg` value is present in port_config.ini, the value from the minigraph will take precedence, overriding that value.

Also remove `AutoNegotiation` and `EnableAutoNegotiation` elements from the `DeviceInfo` section, as we will use this data in the `LinkMetadata` section to determine whether to enable auto-negotiation for a port.

Author: jleveque

src/sonic-config-engine/minigraph.py

@@ -422,6 +422,7 @@ def parse_linkmeta(meta, hname):
     for linkmeta in link.findall(str(QName(ns1, "LinkMetadata"))):
         port = None
         fec_disabled = None
+        auto_negotiation = None
 
         # Sample: ARISTA05T1:Ethernet1/33;switch-t0:fortyGigE0/4
         key = linkmeta.find(str(QName(ns1, "Key"))).text
@@ -441,10 +442,14 @@ def parse_linkmeta(meta, hname):
             value = device_property.find(str(QName(ns1, "Value"))).text
             if name == "FECDisabled":
                 fec_disabled = value
+            elif name == "AutoNegotiation":
+                auto_negotiation = value
 
         linkmetas[port] = {}
         if fec_disabled:
             linkmetas[port]["FECDisabled"] = fec_disabled
+        if auto_negotiation:
+            linkmetas[port]["AutoNegotiation"] = auto_negotiation
     return linkmetas
 
 
@@ -638,6 +643,11 @@ def parse_xml(filename, platform=None, port_config_file=None):
         if port.get('speed') == '100000' and linkmetas.get(alias, {}).get('FECDisabled', '').lower() != 'true':
             port['fec'] = 'rs'
 
+        # If AutoNegotiation is available in the minigraph, we override any value we may have received from port_config.ini
+        autoneg = linkmetas.get(alias, {}).get('AutoNegotiation')
+        if autoneg:
+            port['autoneg'] = '1' if autoneg.lower() == 'true' else '0'
+
     # set port description if parsed from deviceinfo
     for port_name in port_descriptions:
         # ignore port not in port_config.ini