softfloat: Tidy a * b + inf return

No reason to set values in 'a', when we already
have float_class_inf in 'c', and can flip that sign.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed