MdeModulePkg: Enable Data Terminal at end of serial

When a Serial device resets, the Modem Control Register Data Terminal
Ready and Request to Send need to be cleared also. Otherwise the
registers will be left in their previous state, and the connected device
will not be able to transmit data.

Signed-off-by: Kenneth Lautner <kenlautner3@gmail.com>

MdeModulePkg/Universal/Console/TerminalDxe/TerminalConIn.c

@@ -95,6 +95,10 @@ TerminalConInReset (
       );
   }
 
+  if (!EFI_ERROR (Status)) {
+    Status = TerminalDevice->SerialIo->SetControl (TerminalDevice->SerialIo, EFI_SERIAL_DATA_TERMINAL_READY|EFI_SERIAL_REQUEST_TO_SEND);
+  }
+
   return Status;
 }