m68k: bsd: Change type from char * to gdb_byte *

	* m68k-bsd-nat.c (m68kbsd_supply_gregset): Change type of regs to
	gdb_byte *.
	* m68k-bsd-nat.c (m68kbsd_supply_fpregset): Likewise.
	* m68k-bsd-nat.c (m68kbsd_collect_gregset): Likewise.
	* m68k-bsd-nat.c (m68kbsd_supply_pcb): Cast &tmp to gdb_byte *.