postproc: fix unaligned access

QP_store is only 8-bit-aligned, so accessing it as uint32_t causes
SIGBUS crashes on sparc.
The AV_RN32/AV_WN32 macros only do unaligned access in the
HAVE_FAST_UNALIGNED case.
Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

libpostproc/postprocess.c

@@ -76,6 +76,7 @@ try to unroll inner for(x=0 ... loop to avoid these damn if(x ... checks
 #include "config.h"
 #include "libavutil/avutil.h"
 #include "libavutil/avassert.h"
+#include "libavutil/intreadwrite.h"
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -997,7 +998,7 @@ void  pp_postprocess(const uint8_t * src[3], const int srcStride[3],
             int i;
             const int count= FFMAX(mbHeight * QPStride, mbWidth);
             for(i=0; i<(count>>2); i++){
-                ((uint32_t*)c->nonBQPTable)[i] = ((const uint32_t*)QP_store)[i] & 0x3F3F3F3F;
+                AV_WN32(c->nonBQPTable + (i<<2), AV_RN32(QP_store + (i<<2)) & 0x3F3F3F3F);
             }
             for(i<<=2; i<count; i++){
                 c->nonBQPTable[i] = QP_store[i] & 0x3F;