anv: Ignore some CreateInfo structs when rasterization is disabled

According to the description of VkGraphicsPipelineCreateInfo(),
pViewportState, pMultisampleState, pDepthStencilState and
pColorBlendState must be ignored when rasterization is not enabled.

This avoids potentially invalid pointers being dereferenced when
rasterization is disabled.  Tested with `demos_x64 VK_Parameter_Zoo`
from Renderdoc repository.

v2: Don't store the `raster_enabled` as part of anv_pipeline, just
    query it from the create info.  This avoids storing a state that's
    only used during pipeline creation. (Jason)

Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2258


Cc: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Eric Engestrom <eric@engestrom.ch> [v1]
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> [v1]
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
(cherry picked from commit 75a19186)