amd/vpelib: Change Max DS support to 4:1

Since VPE can use upto 8 taps, for quality purpose vpelib cannot support
downscaling ratio more than 4:1. The caps value needed to be modified to
reject this case earlier.

Reviewed-by: Roy Chan <Roy.Chan@amd.com>
Acked-by: Jack Chih <chiachih@amd.com>
Signed-off-by: Navid Assadian <navid.assadian@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30531>

src/amd/vpelib/src/chip/vpe10/vpe10_resource.c

@@ -160,8 +160,12 @@ static struct vpe_caps caps = {
                 .yuy2                                        = 0},
             .max_upscale_factor          = 64000,
 
-            // 6:1 downscaling ratio: 1000/6 = 166.666
-            .max_downscale_factor = 167,
+            /*
+             * 4:1 downscaling ratio : 1000 / 4 = 250
+             * vpelib does not support more than 4:1 to preserve quality
+             * due to the limitation of using maximum number of 8 taps
+            */
+            .max_downscale_factor = 250,
 
             .pitch_alignment    = 256,
             .addr_alignment     = 256,