[PATCH] Fix apparent code overlap in ppc64 head.S

An #if/#else construct near the top of ppc64's head.S appears to
create overlapping sections of code for iSeries and pSeries (i.e. one
thing on iSeries and something different in the same place on
pSeries).  In fact, checking the various absolute offsets, it doesn't.
This patch unravels the #ifdefs to make it more obvious what's going
on.  This accomplishes another microstep towards a single kernel image
which can boot both iSeries and pSeries.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>