devres: support sizes greater than an unsigned long

As in 4f452e8a, use resource_size_t
to accomodate sizes greater than the size of an unsigned long int on
platforms that have more than 32 bit physical addresses.

Signed-off-by: Cristian Stoica <cristian.stoica@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>