Pull tty / serial driver updates from Greg KH:
 "Here is the "large" TTY and Serial driver update for 5.3-rc1.

  It's in the negative number of lines overall as we removed an obsolete
  serial driver that was causing problems for some people who were
  trying to clean up some apis (the mpsc.c driver, which only worked for
  some pre-production hardware that no one has anymore.)

  Other than that, lots of tiny changes, cleaning up small things along
  with some platform-specific serial driver updates.

  All of these have been in linux-next for a while now with no reported
  issues"

* tag 'tty-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (68 commits)
  tty: serial: fsl_lpuart: add imx8qxp support
  serial: imx: set_termios(): preserve RTS state
  serial: imx: set_termios(): clarify RTS/CTS bits calculation
  serial: imx: set_termios(): factor-out 'ucr2' initial value
  serial: sh-sci: Terminate TX DMA during buffer flushing
  serial: sh-sci: Fix TX DMA buffer flushing and workqueue races
  serial: mpsc: Remove obsolete MPSC driver
  serial: 8250: 8250_core: Fix missing unlock on error in serial8250_register_8250_port()
  serial: stm32: add RX and TX FIFO flush
  serial: stm32: add support of RX FIFO threshold
  serial: stm32: add support of TX FIFO threshold
  serial: stm32: update PIO transmission
  serial: stm32: add support of timeout interrupt for RX
  Revert "serial: 8250: Don't service RX FIFO if interrupts are disabled"
  tty/serial/8250: use mctrl_gpio helpers
  serial: mctrl_gpio: Check if GPIO property exisits before requesting it
  serial: 8250: pericom_do_set_divisor can be static
  tty: serial_core: Set port active bit in uart_port_activate
  serial: 8250: Add MSR/MCR TIOCM conversion wrapper functions
  serial: 8250: factor out serial8250_{set,clear}_THRI() helpers
  ...