arm-pe objdump -P

arm-pe looks to be a very old PE implementation, incompatible with
current arm-wince-pe.  arm-pe has different relocations and uses
ARMMAGIC which has this comment: "I just made this up".  Well, OK, I
don't know the history but it was probably before Microsoft "just made
up" their constants for ARM windows CE.

This patch supports objdump -P for arm-pe, and another magic constant
that may appear in object files.  (I don't think binutils generates
files using ARMV7PEMAGIC aka IMAGE_FILE_MACHINE_ARMNT.)

	* od-pe.c (is_pe_object_magic): Handle IMAGE_FILE_MACHINE_ARMNT
	and ARMMAGIC.