serial: 8250_lpss: Switch over to MSI interrupts

Some devices support MSI interrupts. Let's at least try to use them in
platforms that provide MSI capability.

While at that, remove the now duplicated code from qrp_serial_setup().

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Link: https://lore.kernel.org/r/20191001115825.795700-1-felipe.balbi@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>