gallium/auxiliary/vl: Fix duplicate symbol build errors.

gallium/auxiliary/vl: Fix duplicate symbol build errors.

  CXXLD    gallium_dri.la
duplicate symbol _compute_shader_video_buffer in:
    ../../../../src/gallium/auxiliary/.libs/libgalliumvl.a(libgalliumvl_la-vl_compositor.o)
    ../../../../src/gallium/auxiliary/.libs/libgalliumvl.a(libgalliumvl_la-vl_compositor_cs.o)
duplicate symbol _compute_shader_weave in:
    ../../../../src/gallium/auxiliary/.libs/libgalliumvl.a(libgalliumvl_la-vl_compositor.o)
    ../../../../src/gallium/auxiliary/.libs/libgalliumvl.a(libgalliumvl_la-vl_compositor_cs.o)
duplicate symbol _compute_shader_rgba in:
    ../../../../src/gallium/auxiliary/.libs/libgalliumvl.a(libgalliumvl_la-vl_compositor.o)
    ../../../../src/gallium/auxiliary/.libs/libgalliumvl.a(libgalliumvl_la-vl_compositor_cs.o)

Fixes: 9364d66cb7f7 ("gallium/auxiliary/vl: Add video compositor compute shader render")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: James Zhu <James.Zhu@amd.com>