m68k/math-emu: Remove unnecessary code

Remove unnecessary code that matches this coccinelle pattern

	if (...)
		return ret;
	return ret;
Signed-off-by: Greg Dietsche <Gregory.Dietsche@cuw.edu>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/math-emu/fp_log.c

@@ -105,9 +105,6 @@ fp_fetoxm1(struct fp_ext *dest, struct fp_ext *src)
 
 	fp_monadic_check(dest, src);
 
-	if (IS_ZERO(dest))
-		return dest;
-
 	return dest;
 }