fix print_size printing fractional gigabyte numbers on 32-bit platforms

In print_size(), the math that calculates the fractional remainder of a number
used the same integer size as a physical address.  However, the "10 *" factor
of the algorithm means that a large number (e.g. 1.5GB) can overflow the
integer if we're running on a 32-bit system.  Therefore, we need to
disassociate this function from the size of a physical address.

Signed-off-by: Timur Tabi <timur@freescale.com>