Pull tty/serial fixes from Greg KH:
"Here are a few tty/serial fixes for 3.15-rc3 that resolve a number of
reported issues in the 8250 and samsung serial drivers, as well as a
character loss fix for the tty core that was caused by the lock
removal patches a release ago"
* tag 'tty-3.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial_core: fix uart PORT_UNKNOWN handling
serial: samsung: Change barrier() to cpu_relax() in console output
serial: samsung: don't check config for every character
serial: samsung: Use the passed in "port", fixing kgdb w/ no console
serial: 8250: Fix thread unsafe __dma_tx_complete function
8250_core: Fix unwanted TX chars write
tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc