powerpc/papr_scm: Update DT properties

The ibm,unit-sizes property was originally specified as an array of two
u32s corresponding to the memory block size, and the number of blocks
available in that region. A fairly last-minute change to the SCM DT
specification was splitting that into two seperate u64 properties:
ibm,block-sizes and ibm,number-of-blocks that convey the same
information. No firmware / hypervisor that emitted the ibm,unit-size
property ever appeared in the wild.

Fixes: b5beae5e ("powerpc/pseries: Add driver for PAPR SCM regions")
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Use kernel types (u32/u64)]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>