postprocess_template: put rsp on the clobber list to prevent gcc from using it in "q"

Fixes Ticket2675
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libpostproc/postprocess_template.c

@@ -1313,7 +1313,7 @@ DERING_CORE((%0, %1, 8)    ,(%%REGd, %1, 4),%%mm2,%%mm4,%%mm0,%%mm3,%%mm5,%%mm1,
 
         "1:                        \n\t"
         : : "r" (src), "r" ((x86_reg)stride), "m" (c->pQPb), "m"(c->pQPb2), "q"(tmp)
-        : "%"REG_a, "%"REG_d
+        : "%"REG_a, "%"REG_d, "%"REG_SP
     );
 #else // HAVE_7REGS && (TEMPLATE_PP_MMXEXT || TEMPLATE_PP_3DNOW)
     int y;