MIPS: Remove remains of legacy remote target support
    
    Complement commit f7c382926d78 ("Remove support for "target m32rsdi" and
    "target mips/pmon/ddb/rockhopper/lsi"") and remove dead MIPS target code
    which used to support these legacy remote targets.
    
    	gdb/
    	* mips-tdep.c (mips_r3041_reg_names): Remove.
    	(mips_breakpoint_from_pc): Remove IDT and PMON breakpoint
    	encodings.