tty: Always detach from initial TTY and open actual /dev/ttyN

This patch fixes a long standing problem with TTY's.  The original code
tried to workaround a limitation in the console of some embedded systems
that was detrimental on actual TTYs.

As an added benefit, the console specific "Press Enter" prompt for the
console port is now available on all TTYs -- meaning no getty needs to
be started and kept needlessly in the background until it is needed.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

helpers.h

@@ -81,7 +81,7 @@ void    set_hostname    (char **hostname);
 int     complete        (char *cmd, int pid);
 int     run             (char *cmd);
 int     run_interactive (char *cmd, char *fmt, ...);
-pid_t   run_getty       (char *cmd, char *args[], int console);
+pid_t   run_getty       (char *cmd, char *args[], char *tty, int console);
 int     run_parts       (char *dir, char *cmd);
 
 #endif /* FINIT_HELPERS_H_ */