aspeed: Remove usage of sysbus_mmio_map

aspeed: Remove usage of sysbus_mmio_map

sysbus_mmio_map maps devices into "get_system_memory()".

With the new SoC memory attribute, we want to make sure that each device is
mapped into the SoC memory.

In single SoC machines, the SoC memory is the same as "get_system_memory()",
but in multi SoC machines it will be different.

Signed-off-by: Peter Delevoryas <pdel@fb.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220624003701.1363500-4-pdel@fb.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>