Remove divsf3.c from compiler-rt

We implement this now!

build.rs

@@ -4497,9 +4497,7 @@ mod c {
                 "ctzdi2.c",
                 "ctzsi2.c",
                 "divdc3.c",
-                "divdf3.c",
                 "divsc3.c",
-                "divsf3.c",
                 "divxc3.c",
                 "extendsfdf2.c",
                 "extendhfsf2.c",