anv: remove multiple push descriptors

anv: remove multiple push descriptors

VUID-VkPipelineLayoutCreateInfo-pSetLayouts-00293

   pSetLayouts must not contain more than one descriptor set layout
   that was created with
   VK_DESCRIPTOR_SET_LAYOUT_CREATE_PUSH_DESCRIPTOR_BIT_KHR set

There is only one push descriptor set with all the descriptor sets, so
no need to have an array.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19050>