pvr: do not claim support for ASTC texture compression

pvr: do not claim support for ASTC texture compression

We don't support any ASTC formats yet, but the textureCompressionASTC_LDR
feature was incorrectly set to true. Fix this by setting it to false and
don't advertise ASTC support for texture compression.

Fixes dEQP-VK.api.info.format_properties.compressed_formats

Fixes: 8991e646 ("pvr: Add a Vulkan driver for Imagination Technologies PowerVR Rogue GPUs")
Signed-off-by: Luigi Santivetti <luigi.santivetti@imgtec.com>
Reviewed-by: Karmjit Mahil <Karmjit.Mahil@imgtec.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24448>