[PATCH] Remove NACA fixed address constraint

Comments in head.S suggest that the iSeries naca has a fixed address,
because tools expect to find it there.  The only tool which appears to
access the naca is addRamDisk, but both the in-kernel version and the
version used in RHEL and SuSE in fact locate the NACA the same way as
the hypervisor does, by following the pointer in the hvReleaseData
structure.

Since the requirement for a fixed address seems to be obsolete, this
patch removes the naca from head.S and replaces it with a normal C
initializer.

For good measure, it removes an old version of addRamDisk.c which was
sitting, unused, in the ppc32 tree.

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