anv: Rename get_image_format_properties()
The name is misleading. It looks like vkGetPhysicalDeviceImageFormatProperties(), but it actually implement vkGetPhysicalDeviceFormatProperties. Let's rename it to what it actually does, get_image_format_features(), because it returns VkFormatFeatureFlags. For consistency, also rename get_buffer_format_properties() to get_buffer_format_features().