powerpc/cpm: Move CPMFCR_* defines into cpm.h

The bits are generic to CPM devices, so let's move them to the
common header file, so drivers won't need to privately reintroduce
another bunch of the same bits (as we can't include cpm2.h header
together with cpm1.h).

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>