Fixes implementation of hardware multiply/divide peripheral in RL78 G13 cores.

Fixes implementation of hardware multiply/divide peripheral in RL78 G13 cores.

	* load.c (rl78_load): If the G10, G13 or G14 flag bits are set in
	the ELF header use them to select the proper emulation mode.
	* mem.c (mem_put_byte): Use mem_put_hi to store a value into the
	MDB register.
	(mem_get_byte): Use mem_get_hi to extract a value from the MDB
	register.