[PATCH] powerpc: Add ibm,pft-size to iSeries device tree

To make iSeries just a teensy bit less special, create ibm,pft-size properties
in the iSeries device tree. We can then rely on htab_dt_scan_pftsize() to set
ppc64_pft_size for us.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>