MIPS/opcodes: Reorder ELF file header flag handling in disassembler

MIPS/opcodes: Reorder ELF file header flag handling in disassembler

Move ELF file header flag interpretation code, used to set disassembler
options, beyond architecture setup.  No functional change as the effects
of both code sections are disjoint from each other, but this provides
for a further expansion of ELF file header flag interpretation.

	opcodes/
	* mips-dis.c (set_default_mips_dis_options): Reorder ELF file
	header flag interpretation code.