v3dv: expose geometry shaders

A run of dEQP-VK.*geom* has 6328 test passes and 16 failures. 14 of
these failures are related to a CTS bug affecting atomic operations
for which I submitted a CL to Khronos. Another fail looks like it might
be a case of the error threshold in CTS being slightly low. There is
only one test fail in that list that looks like it might be an actual
driver bug, but it is a variable pointers test, so it might be unrelated
to geometry shaders in the end.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11783>