isl always aligned the row pitch to the surface's image alignment. This
was sometimes wrong when the surface backed a VkBuffer. For a VkBuffer,
the surface's row pitch is set by VkBufferImageCopy::bufferRowLength,
whose required alignment is only that of the VkFormat.
In particular, VkBuffer rows are packed in many dEQP and Crucible tests.
And packed rows are rarely aligned to the surface's image alignment.
Fixes: dEQP-VK.pipeline.image.view_type.2d.format.r8g8b8a8_unorm.size.13x13
When aligning to isl_format_layout::bs (which is the number of bytes in
the pixel), use isl_align_npot() instead of isl_align(), because
isl_align() works only for power-of-2 alignment.
Fixes assertion in
dEQP-VK.pipeline.image.view_type.1d.format.r16g16b16_sfloat.size.512x1.
The function calculates the offset to a subimage within the surface, in
units of surface samples.
All unit tests pass with `make check`. (Admittedly, though, there are
too few unit tests).
The plan all along was to eventualyl move isl out of the Vulkan
directory, because I intended i965 and anvil to share it.
A small problem I encountered when attempting to write unit tests for
isl precipitated the move. I discovered that it's easier to get isl
unit tests to build if I remove the extra, unneeded dependencies
injected by src/vulkan/Makefile.am. And the easiest way to remove those
unneeded dependencies is to move isl out of src/vulkan. (Unit tests come
in subsequent commits).
