Oops, forgot to compile the VMALLOCBASE/VMALLOC_START patch on
iSeries.  VMALLOC_START is defined in pgtable.h whereas previously
VMALLOCBASE was previously defined in page.h.  lparmap.c needs to be
updated appropriately.

Booted on iSeries RS64 (now).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>