Don't include libbfd.h outside of bfd, part 2

Make bfd_default_set_arch_mach available to a bunch of gas backend
files.

bfd/
	* archures.c (bfd_default_set_arch_mach): Make available in bfd.h.
	* libbfd.h: Regenerate.
	* bfd-in2.h: Regenerate.
gas/
	* config/tc-epiphany.c: Don't include libbfd.h.
	* config/tc-frv.c: Likewise.
	* config/tc-ip2k.c: Likewise.
	* config/tc-iq2000.c: Likewise.
	* config/tc-m32c.c: Likewise.
	* config/tc-mep.c: Likewise.
	* config/tc-mt.c: Likewise.
	* config/tc-nios2.c: Likewise.