Make DumpState and endian conversion routines available for arch-specific dump
code by moving into dump.h. DumpState will be needed by arch-specific dump
code to access target endian information from DumpState->ArchDumpInfo. Also
break the dependency of dump.h from stubs/dump.c by creating a separate
dump-arch.h.

This patch doesn't change any functionality.

Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
[ rebased on top of current master branch,
  renamed endian helpers to cpu_to_dump{16,32,64},
  pass a DumpState * argument to endian helpers,
  Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
[agraf: fix to apply]
Signed-off-by: Alexander Graf <agraf@suse.de>