MIPS16/opcodes: Make the handling of BREAK and SDBBP consistent

MIPS16/opcodes: Make the handling of BREAK and SDBBP consistent

Disassemble the MIPS16 BREAK and SDBBP instruction's immediate operand
in the hexadecimal rather than decimal numeral system and add respective
operandless variants with an implicit 0 operand, making our handling of
these instructions consistent with how we have processed their regular
MIPS and microMIPS counterparts since forever.

	opcodes/
	* mips16-opc.c (decode_mips16_operand) <'6'>: Switch the operand
	type to hexadecimal.
	(mips16_opcodes): Add operandless "break" and "sdbbp" entries.

	binutils/
	* testsuite/binutils-all/mips/mips16-extend-insn.d: Adjust BREAK
	and SDBBP disassembly.

	gas/
	* testsuite/gas/mips/mips16.d: Adjust BREAK disassembly.
	* testsuite/gas/mips/mips16-64@mips16.d: Likewise.
	* testsuite/gas/mips/mips16-64.d: Likewise.
	* testsuite/gas/mips/mips16-64@mips16-64.d: Likewise.
	* testsuite/gas/mips/mips16-macro.d: Likewise.
	* testsuite/gas/mips/mips16-64@mips16-macro.d: Likewise.
	* testsuite/gas/mips/mips16-sub.d: Likewise.
	* testsuite/gas/mips/mips16-32@mips16-sub.d: Likewise.