serial: 8250_fintek: Set maximum FIFO of F81216H

The Fintek F81216H had maximum 128Bytes FIFO, but some BIOS configurated
as normal 16Bytes FIFO. This patch will set 128Bytes FIFO and trigger
level multiplier as 4x when F81216H detected.

Default 16550A trigger level is 8Bytes. When this patch applied, the
trigger level will change to 8Byte x 4 = 32Byte. It can be reduce the RX
incoming interrupts.

Suggested-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>