xsysace: Fix driver to use resource_size_t instead of unsigned long

This patch is a bug fix to the SystemACE driver to use resource_size_t
for physical address instead of unsigned long.  This makes the driver
work correctly on 32 bit systems with 64-bit resources (e.g. PowerPC 440).

Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>