cris: dynobj mach

A comment in cris check_relocs bemoans not being able to access the
output bfd in adjust_dynamic_symbol.  A little over three years after
the comment was written, commit f13a99db51c0 gave that access.  So
let's make use of it and remove a restriction.

	* elf32-cris.c (elf_cris_adjust_dynamic_symbol): Get mach from
	output bfd, not dynobj.
	(cris_elf_check_relocs): Remove dynobj mach check.