Why are 'powerpc' DTS files found in the 'boot/fdt/dts/arm' directory?

[John Clark]

For example, in my most recent, as of March 29, 2014 svn snapshot, I find:

./boot/fdt/dts/arm/p1020rdb.dts

Where as ./boot/fdt/dts/powerpc

only has:

mpc8555cds.dts	mpc8572ds.dts

What gives?

John Clark.