libpci: physmem-windows: Fix check for length param of physmem_unmap()

libpci: physmem-windows: Fix check for length param of physmem_unmap()

VirtualQuery() does not have to return whole mapped range, but just region
subset. So call VirtualQuery() multiple times for each region and calculate
the total length of the mapping.

This change fixes unmapping of the BIOS 0xE0000-0x100000 memory for which
Windows creates region of one page and so VirtualQuery() for each region i
at virtual address ptr + i*4096 returns AllocationBase=ptr and RegionSize=4096.