virgl: Increase the shader transfer buffer by doubling the size
With only linearly increasing the size of the shader transfer buffer the transfer of very large shaders may fail, so with each attempt double the size of the buffer.
CTS: dEQP-GLES31.functional.ssbo.layout.random.all_shared_buffer.48 for VTK-GL-CTS b5dcfb9c5 and newer
virglrenderer bug: virgl/virglrenderer#150 (closed)
Fixes: a8987b88 virgl: add driver for virtio-gpu 3D (v2)
Edited by Gert Wollny