Running a graphics adapter on the MACCHIATObin fails due to an
insufficiently sized memory window.

Enlarge the memory window for the PCIe slot to 512 MiB.

With the patch I am able to use a GT710 graphics adapter with 1 GB onboard
memory.

These are the mapped memory areas that the graphics adapter is actually
using:

Region 0: Memory at cc000000 (32-bit, non-prefetchable) [size=16M]
Region 1: Memory at c0000000 (64-bit, prefetchable) [size=128M]
Region 3: Memory at c8000000 (64-bit, prefetchable) [size=32M]
Region 5: I/O ports at 1000 [size=128]
Expansion ROM at ca000000 [disabled] [size=512K]
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: NGregory CLEMENT <gregory.clement@bootlin.com>