MIPS/opcodes: Correct mixed MIPS16 and microMIPS disassembly

MIPS/opcodes: Correct mixed MIPS16 and microMIPS disassembly

Mixing MIPS16 and microMIPS code in a single binary isn't usually
supported but GAS happily produces such code if requested.  However it
is not correctly disassembled even if a symbol table is available and
function symbols are correctly anotated with the ISA mode.  This is
because the ELF-header global microMIPS ASE flag takes precedence over
MIPS16 function annotation, causing them to be treated as regular MIPS
code.

Correct the problem by respecting function symbol anotation regardless
of the ELF-header flag.

	binutils/
	* testsuite/binutils-all/mips/mixed-mips16-micromips.d: New test.
	* testsuite/binutils-all/mips/mixed-mips16-micromips.s: New test
	source.
	* testsuite/binutils-all/mips/mips.exp: Run the new test.

	opcodes/
	* mips-dis.c (is_compressed_mode_p): Add `micromips_p' operand,
	replacing references to `micromips_ase' throughout.
	(_print_insn_mips): Don't use file-level microMIPS annotation to
	determine the disassembly mode with the symbol table.