kms: kmsbufferpool won't return false, when the input size won't apply to it

Submitted by Randy Li (ayaka)

Link to original bug (#795173)

Description

The kmsbufferpool will the use its priv->vinfo to alloc a buffer.
The priv->vinfo comes from the caps in the gst_kms_buffer_pool_set_config(), parsed from the input bufferpool config.

The size parameters in bufferpool config won't parsed, even it did in the set_config(), it won't apply to the bufferpool as well.

As I said, the kmsbufferpool would use its' priv->vinfo to make a buffer, while the size filed from that GstVideoInfo is ignored. The kmsbufferpool would use the width, height and video pixel format information to calculate the reuqest size to the kernel's drm interface, then using the feedback size from the kernel to update the size filed in its priv->vinfo.

When I apply a size parameter for the kmsbufferpool, it won't take effect at all, so the changing configure of the kmsbufferpool is not success at this time. It should returen an negative result(return FALSE).