hw/pci-host/astro: Add LMMIO range support

hw/pci-host/astro: Add LMMIO range support

Each Astro on 64-bit machines supports up to four LMMIO regions.
Those regions are used by graphic cards and other PCI devices which
need to map huge memory areas. The LMMIO regions are configured and
set up by SeaBIOS-hppa and then used as-is by the operating systems
(Linux, HP-UX).

With this addition it's now possible to add other PCI graphic
cards on the command line, e.g. with "-device ati-vga".

Signed-off-by: Helge Deller <deller@gmx.de>