serial: 8250_pci1xxxx: Drop quirk from 8250_port

serial: 8250_pci1xxxx: Drop quirk from 8250_port

We are not supposed to spread quirks in 8250_port module especially
when we have a separate driver for the hardware in question.

Move quirk from generic module to the driver that uses it.

While at it, move IO to ->set_divisor() callback as it has to be from
day 1. ->get_divisor() is not supposed to perform any IO as UART port:
- might not be powered on
- is not locked by a spin lock

Fixes: 1ed67ecd1349 ("8250: microchip: Add 4 Mbps support in PCI1XXXX UART")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rengarajan S <rengarajan.s@microchip.com>
Link: https://lore.kernel.org/r/20240219162917.2159736-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>