vmm: Remove concept of "input_enabled"

This concept ends up being broken with multiple types on input connected
e.g. console on TTY and serial on PTY. Already the code for checking for
injecting into the serial device checks that the serial is configured.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/config.rs

@@ -1452,12 +1452,6 @@ pub enum ConsoleOutputMode {
     Null,
 }
 
-impl ConsoleOutputMode {
-    pub fn input_enabled(&self) -> bool {
-        matches!(self, ConsoleOutputMode::Tty | ConsoleOutputMode::Pty)
-    }
-}
-
 #[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
 pub struct ConsoleConfig {
     #[serde(default = "default_consoleconfig_file")]