Handling of mips disassembly by gdb

[Will Cohen]

The disassembly performed by the function _print_insn_mips in
opcode/mips-dis.c is dependent on the mach field of the struct info
passed to the function.  Unfortunately the mach field is alway set to
zero because TM_PRINT_INSN_MACH is defined to be 0 in
gdb/config/mips/tm-mip.h.  Is there a reason that this must be set to
zero?  Wouldn't it be more appropriate to set it to
((TARGET_PRINT_INSN_INFO)->mach)? Changing this line allows the
disassembler to generate model specific instructions.

Should I generate a patch to fix this and submit it to binutils?  Or is
there a reason this define was set to zero?

-Will