Revert "ifconfig: abort if loading a module fails other than for ENOENT"

This reverts commit 2c24ad3377.

This change causes some commands to fail, for example when working with
renamed interfaces or when trying to list a nonexistent interface by
name.

PR:		269042
Reported by:	dbaio, Michael Paepcke <bugs.fbsd@paepcke.de>
MFC with:	2c24ad3377

sbin/ifconfig/ifconfig.c

@@ -1719,19 +1719,11 @@ ifmaybeload(const char *name)
 		}
 	}
 
-	/* Try to load the module. */
-	if (kldload(ifkind) < 0) {
-		switch (errno) {
-		case ENOENT:
-			/*
-			 * Ignore ENOENT, because ifconfig can't infer the
-			 * names of all drivers (eg mlx4en(4)).
-			 */
-			break;
-		default:
-			err(1, "kldload(%s)", ifkind);
-		}
-	}
+	/*
+	 * Try to load the module.  But ignore failures, because ifconfig can't
+	 * infer the names of all drivers (eg mlx4en(4)).
+	 */
+	(void) kldload(ifkind);
 }
 
 static struct cmd basic_cmds[] = {