Don't allow memoryless storage for VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT.
Memoryless storage for VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT descriptors
requires support for, and use of, shader framebuffer fetch.
Remove compile-time checking for MVK_APPLE_SILICON before disabling memoryless storage
for buffers and images, since the requirement exists for all platforms, and memoryless
storage will already otherwise be disabled on other platforms anyway.
776719106c