lavfi/scale_qsv: change alignment to be 16 bytes

32 bytes alignment is not needed and increases the failure possibilty of
SFC (low power scaling mode)

Signed-off-by: Zhong Li <zhong.li@intel.com>

libavfilter/vf_scale_qsv.c

@@ -201,8 +201,8 @@ static int init_out_pool(AVFilterContext *ctx,
     out_frames_hwctx = out_frames_ctx->hwctx;
 
     out_frames_ctx->format            = AV_PIX_FMT_QSV;
-    out_frames_ctx->width             = FFALIGN(out_width,  32);
-    out_frames_ctx->height            = FFALIGN(out_height, 32);
+    out_frames_ctx->width             = FFALIGN(out_width,  16);
+    out_frames_ctx->height            = FFALIGN(out_height, 16);
     out_frames_ctx->sw_format         = out_format;
     out_frames_ctx->initial_pool_size = 4;