PNP / ACPI: use unsigned int in pnpacpi_encode_resources()

use unsigned int for port, irq, dma and mem used for pnp_get_resource()
This fixes gcc warnings of type "conversion to unsigned int
from int may change the sign of the result"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>