fix alignment of allocated memory in AllocateTransformBuffer
fix alignment of allocated memory in AllocateTransformBuffer

likely to avoid unaligned reads in the future

Change-Id: I434ba17c139ad6e190ebd9b909b241c6c6f1e7f8

ttyangf/libwebp,ttyangf/libwebp,Aexyn/libwebp,Aexyn/libwebp,PKRoma/libwebp,redengineer/libwebp,redengineer/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,Aexyn/libwebp,redengineer/libwebp,ttyangf/libwebp,webmproject/libwebp,redengineer/libwebp,webmproject/libwebp,webmproject/libwebp,Aexyn/libwebp,PKRoma/libwebp,redengineer/libwebp,ttyangf/libwebp,PKRoma/libwebp,ttyangf/libwebp,PKRoma/libwebp,webmproject/libwebp,Aexyn/libwebp