asm-ppc64/imalloc.h is only included from files in arch/powerpc/mm.
We already have a header for mm local definitions,
arch/powerpc/mm/mmu_decl.h.  Thus, this patch moves the contents of
imalloc.h into mmu_decl.h.  The only exception are the definitions of
PHBS_IO_BASE, IMALLOC_BASE and IMALLOC_END.  Those are moved into
pgtable.h, next to similar definitions of VMALLOC_START and
VMALLOC_SIZE.

Built for multiplatform 32bit and 64bit (ARCH=powerpc).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>