uart_register_driver — register a driver with the uart core layer
|struct uart_driver * drv|
Register a uart driver with the core driver. We in turn register with the tty layer, and initialise the core driver per-port state.
We have a proc file in /proc/tty/driver which is named after the normal driver.
drv->port should be NULL, and the per-port structures should be registered using uart_add_one_port after this call has succeeded.