svga/ci: Increase vmware-vmx-piglit job parallelism to 4

Bump up vmware farm's vmware-vmx-piglit job parallelism to 4.

Signed-off-by: Martin Krastev <martin.krastev@broadcom.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34925>
1 file changed