rl78.c (register_sizes): Make the "upper half" of %fp 2 to keep registers after it properly word-aligned.

	* config/rl78/rl78.c (register_sizes): Make the "upper half" of
	%fp 2 to keep registers after it properly word-aligned.
	(rl78_alloc_physical_registers_umul): Handle the case where both
	input operands are the same.

Co-Authored-By: DJ Delorie <dj@redhat.com>

From-SVN: r207308