alpha: Improve sysdeps/alpha/divqu.S and sysdeps/alpha/remqu.S

	* sysdeps/alpha/divqu.S (__divqu): Move save of $f0 and excb after
	conditional branch to DIVBYZERO.  Fix unwind info.
	* sysdeps/alpha/remqu.S (__remqu): Move saves of $f0, $f1, $f2 and
	excb after conditional branch to $powerof2.  Add missing unop
	instructions and .align directives and reorder instructions to
	match __divqu.

Signed-off-by: Uroš Bizjak <ubizjak@gmail.com>