macloader: Drop semcove case and enum

The all_ranges structure has one entry less than MAX_TYPES because
semcove type is not defined there, but there's no check for NULL and if
the mac isn't found it segfaults.

Change-Id: Ie218ea0a82b03992085db0f2d1cfc7079e7415a0

macloader/macaddr_mappings.h

@@ -24,7 +24,6 @@ enum Type {
     NONE,
     MURATA,
     SEMCOSH,
-    SEMCOVE,
     SEMCO3RD,
     SEMCO,
     WISOL,

macloader/macloader.c

@@ -190,9 +190,6 @@ int main() {
         case SEMCOSH:
             type_str = "semcosh";
             break;
-        case SEMCOVE:
-            type_str = "semcove";
-            break;
         case SEMCO3RD:
             type_str = "semco3rd";
             break;