[PATCH] ppc64: Remove PTRRELOC() from msChunks code

The msChunks code was written to work on pSeries, but now it's only used on
iSeries. This means there's no need to do PTRRELOC anymore, so remove it all.

A few places were getting "extern reloc_offset()" from abs_addr.h, move it
into system.h instead.

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