hvmloader: fix off-by-one-bit error when initialising PCI devices

hvmloader: fix off-by-one-bit error when initialising PCI devices

hvmloader is responsible for - amoungst other things - initialising
the PCI device BARs prior to loading the guest BIOS.  The previous
code only probed for devfn up to 128.  The lower 3 bits are function
IDs so this meant that only devices in slots 0-15 were actually being
initialized.

Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Acked-by: Gianni Tedesco <gianni.tedesco@citrix.com>