M30 response is missing linefeed, "ok" therefore not on own line

This leads to the command not being acknowledged properly
by the firmware, leading to consecutive issues in host software
waiting for an acknowledgement.

Marlin/cardreader.cpp

     if (file.remove(curDir, fname)) 
     {
       SERIAL_PROTOCOLPGM("File deleted:");
-      SERIAL_PROTOCOL(fname);
+      SERIAL_PROTOCOLLN(fname);
       sdpos = 0;
     }
     else