Implement operators 'lat', 'moprc', 'mopdl', 'mpls', 'pppoed', 'pppoes'

**lat**

BPF code
```
(000) ldh      [12]
(001) jeq      #0x6004          jt 2	jf 3
(002) ret      #65535
(003) ret      #0
```

Lua code:
```
return function(P,length)
   if not (14 <= length) then return false end
   local v1 = ffi.cast("uint16_t*", P+12)[0]
   do return v1 == 1120 end
end
```

**moprc**

BPF code
```
(000) ldh      [12]
(001) jeq      #0x6002          jt 2	jf 3
(002) ret      #65535
(003) ret      #0
```

Lua code:
```
return function(P,length)
   if not (14 <= length) then return false end
   local v1 = ffi.cast("uint16_t*", P+12)[0]
   do return v1 == 608 end
end
```

**mopdl**

BPF code:
```
(000) ldh      [12]
(001) jeq      #0x6001          jt 2	jf 3
(002) ret      #65535
(003) ret      #0
```

Lua code:
```
return function(P,length)
   if not (14 <= length) then return false end
   local v1 = ffi.cast("uint16_t*", P+12)[0]
   do return v1 == 352 end
end
```

**mpls**

BPF code:
```
(000) ldh      [12]
(001) jeq      #0x8847          jt 2	jf 3
(002) ret      #65535
(003) ret      #0
```

Lua code:
```
return function(P,length)
   if not (14 <= length) then return false end
   local v1 = ffi.cast("uint16_t*", P+12)[0]
   do return v1 == 18312 end
end
```

**pppoed**

BPF code:
```
(000) ldh      [12]
(001) jeq      #0x8863          jt 2	jf 3
(002) ret      #65535
(003) ret      #0
```

Lua code:
```
return function(P,length)
   if not (14 <= length) then return false end
   local v1 = ffi.cast("uint16_t*", P+12)[0]
   do return v1 == 25480 end
end
```

**pppoes**

BPF code:
```
(000) ldh      [12]
(001) jeq      #0x8864          jt 2	jf 3
(002) ret      #65535
(003) ret      #0
```

Lua code:
```
return function(P,length)
   if not (14 <= length) then return false end
   local v1 = ffi.cast("uint16_t*", P+12)[0]
   do return v1 == 25736 end
end
```