There's no need for generated files in SysFS to tell you their precise
file size when you stat() them.
I noticed when profiling "find /" that we were spending a chunk of time
generating and throwing away SysFS content just so we could tell you
exactly how large it would be. :^)
This is a bug that went unnoticed for a long time, so the exposed values
in SysFS PCI device directories were incorrect because the assigned PCI
address was simply the host bridge always.
Also, the bus typing should really be two hexadecimal digits and not 4
digits.
