tty fix for linux-3.6.10
fixes list:
1> Makefile ccflags-y change
2> removed linux/config.h
3> remove flip buffer count checking; 3.6.10 uses linked list, no worry about
the count anymore
4> init_MUTEX() removed and use sema_init(&sem,1)
5> added linux/sched.h for set_current_state(TASK_INTERRUPTIBLE)
6> tty_driver{} removed devfs_name field
7> tty_driver{} removed TTY_DRIVER_NO_DEVFS flag
8> tty_operations{} now a separated struct
9>  uart_port{} struct interface change of circ_buf
10> uart_port{} struct info removed
Merge branch 'master' of https://github.com/hunterhu/ldd3-examples-updated