pvr: treat VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT as not supported

pvr: treat VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT as not supported

The required compiler support is missing for mutable format support, so return a
not supported error from vkGetPhysicalDeviceImageFormatProperties2() when the
VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT flag is set in the image format info
structure.

This results in the dEQP-VK.image.mutable.* conformance tests being treated as
Not Supported.

Signed-off-by: Frank Binns <frank.binns@imgtec.com>
Reviewed-by: Karmjit Mahil <Karmjit.Mahil@imgtec.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25241>