* m88k-tdep.c (m88k_breakpoint_from_pc): Change return type to

* m88k-tdep.c (m88k_breakpoint_from_pc): Change return type to
`const gdb_byte *'.  Use gdb_byte for break_insn.
(m88k_return_value): Change type of readbuf and
writebuf arguments to `gdb_byte *'.  Use gdb_byte for buf.
(m88k_supply_gregset): Use `gdb_byte *' for regs.