tools/mfn-dump: Fixes to 'dump-p2m'

tools/mfn-dump: Fixes to 'dump-p2m'

* Don't walk off the end of p2m_table under the mistaken impression that it
  contains toolstack unsigned longs.  Despite its array type it contains guest
  unsigned longs so unconditionally needs casting to the guest width to use
  correctly.  Furthermore, a 64bit toolstack must be extra careful when it
  finds a 32bit guest's INVALID_MFN.

* Drop 'mapped' and 'pinned' descriptions.  This are both bogus, including all
  uses of the is_mapped() macro.

* Rearrange the type name printing to be more concise.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>