8250: microchip: pci1xxxx: Rearranging the structure declarations

Structure declarations in 8250_pci1xxxx.c have been moved above
the functions for code readability.

Signed-off-by: Rengarajan S <rengarajan.s@microchip.com>
Link: https://lore.kernel.org/r/20231215151123.41812-2-rengarajan.s@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>