Revert THRNE-patch. The problem was in u16550_putc

Regarding to:
https://github.com/tanzilli/ariag25-linux-2.6.39/blob/ariag25/drivers/tty/serial/8250.c#L1584
https://github.com/tanzilli/ariag25-linux-2.6.39/blob/ariag25/drivers/tty/serial/8250.c#L1913



When UART_LSR_THRE bit is set, then we ready to transmit more.

Current u16550_putc loops while UART_LSR_THRE bit is set. This logic have to be inverted.

Signed-off-by: Anton D. Kachalov <mouse@yandex-team.ru>