drivers: console: uart_mux: Initial UART muxing support

Create support for muxed UARTs which are attached to a real
UART and which use GSM 07.10 muxing protocol to create virtual
channels that can be run on top of the real UART.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
7 files changed