anv: Add support for sample locations

anv: Add support for sample locations

Allowing the user to set custom sample locations, by filling the
extension structs and chaining them to the pipeline structs according
to the Vulkan specification section [26.5. Custom Sample Locations]
for the following structures:

'VkPipelineSampleLocationsStateCreateInfoEXT'
'VkSampleLocationsInfoEXT'
'VkSampleLocationEXT'

Once custom locations are used, the default locations are lost and need
to be re-emitted again in the next pipeline creation. For that, we emit
the 3DSTATE_SAMPLE_PATTERN at every pipeline creation.

v2: In v1, we used the custom anv_sample struct to store the location
    and the distance from the pixel center because we would then use
    this distance to sort the locations and send them in increasing
    monotonical order to the GPU. That was because the Skylake PRM Vol.
    2a "3DSTATE_SAMPLE_PATTERN" says that the samples must have
    monotonically increasing distance from the pixel center to get the
    correct centroid computation in the device. However, the Vulkan
    spec seems to require that the samples occur in the order provided
    through the API and this requirement is only for the standard
    locations. As long as this only affects centroid calculations as
    the docs say, we should be ok because OpenGL and Vulkan only
    require that the centroid be some lit sample and that it's the same
    for all samples in a pixel; they have no requirement that it be the
    one closest to center. (Jason Ekstrand)
    For that we made the following changes:
    1- We removed the custom structs and functions from anv_private.h
       and anv_sample_locations.h and anv_sample_locations.c (the last
       two files were removed). (Jason Ekstrand)
    2- We modified the macros used to take also the array as parameter
       and we renamed them to start by GEN_. (Jason Ekstrand)
    3- We don't sort the samples anymore. (Jason Ekstrand)

v3 (Jason Ekstrand):
    Break the refactoring out into multiple commits

v4: Merge dynamic/non-dynamic changes into a single commit (Lionel)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/1887>