Remove an unneeded variable increment.

Found using Clang's static analyzer.
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 3f76e91..ab7cfeb 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -2478,7 +2478,6 @@
 
 		/* Eighth byte */
 		*p = flo & 0xFF;
-		p += incr;
 
 		/* Done */
 		return 0;