broadcom/compiler: implement gl_PrimitiveID in FS without a GS

broadcom/compiler: implement gl_PrimitiveID in FS without a GS

OpenGL ES 3.1 specifies that a geometry shader can write to gl_PrimitiveID,
which can then be read by a fragment shader.

OpenGL ES 3.2 additionally adds the capacity for the fragment shader
to read gl_PrimitiveID even if there is no geometry shader. This
commit adds support for this feature, which is also implicitly
expected by the geometry shader feature in Vulkan 1.0.

Fixes:
dEQP-VK.pipeline.framebuffer_attachment.no_attachments
dEQP-VK.pipeline.framebuffer_attachment.no_attachments_ms

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11874>