Retire the synchronous character driver protocol

- change all sync char drivers into async drivers;
- retire support for the sync protocol in libchardev;
- remove async dev style, as this is now the default;
- remove dev_status from VFS;
- clean up now-unused protocol messages.

Change-Id: I6aacff712292f6b29f2ccd51bc1e7d7003723e87

etc/usr/rc

@@ -167,7 +167,7 @@ start)
 
     # Start servers and drivers set at the boot monitor.
     echo -n "Starting services:"
-    up -n random -dev /dev/random -devstyle STYLE_DEVA -period 3HZ
+    up -n random -dev /dev/random -period 3HZ
 
     # load random number generator
     if [ -f $RANDOM_FILE ]
@@ -188,9 +188,9 @@ start)
     done
     if [ X`/bin/sysenv lwip` = Xyes ]
     then
-    	up lwip -script /etc/rs.inet -dev /dev/ip -devstyle STYLE_CLONE_A
+	up lwip -script /etc/rs.inet -dev /dev/ip -devstyle STYLE_CLONE
     else
-    	up inet -script /etc/rs.inet -dev /dev/ip -devstyle STYLE_CLONE
+	up inet -script /etc/rs.inet -dev /dev/ip -devstyle STYLE_CLONE
     fi
 
     up -n ipc