x86: Fix warning about cast from pointer to integer of different size

This patch fixes a warning reported by the kbuild test robot where we were
casting a pointer to a physical address which represents an integer of a
different size.  Per the suggestion of Peter Anvin I am replacing it and one
other spot where I made a similar cast with an unsigned long.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Link: http://lkml.kernel.org/r/20121119182927.3655.7641.stgit@ahduyck-cp1.jf.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>