[OpenBIOS] adding eepom node to sparc64

[Artyom Tarasenko]

Both Linux and MilaX complain about the missing eeprom / rtc-m48t59 node.
Since QEMU actually has this device I tried to add it, but not sure
where is it located.
In sun4u.c it's initialized like this:

nvram = m48t59_init_isa(isa_bus, 0x0074, NVRAM_SIZE, 59);

Is 0x74 the offset to the ISA bus? Then it's wired not as on Ultra-5:

Node 0xf00662d8
                    address:  fffba000
                    reg:  00000014.00000000.00002000
                    model:  'mk48t59'
                    name:  'eeprom'

Here it looks like it had to be aligned to a beginning of a page,
which makes sense because of the large size...
So, where QEMU's 0x74 are coming from?