add etna driver for Vivante GCxxxx embedded GPUs
sync etna driver to 23a0d9e
mesa: main: add GLES internal format override

GLES has no direct way to specify internal format, so we
want to determine the best fit based on format and type and
override the preferred internal format.

This is allowed according to the spec as long as no
specific internal format is provided using extension
OES_required_internalformat. This extension is not
implemented by mesa, though.
oops, fix _mesa_debug call
Revert GL format commits.
st/mesa: improve format selection for GLES
u_gen_mipmap: add temporary workaround for 16 bit textures

The problem is that the GPU requires textures to be tightly packed
but the PE requires a row stride of at least 16 (64/4).
We'll need to implement some solution with a temporary surface in the
driver before this can work.
sync etna driver to 6e4d4cb
sync etna driver to 296195c
sync etna driver to 468ff99
sync etna driver to a6f9e72
u_vbuf: use single vertex buffer if it's not possible to have multiple

Put CONST, VERTEX and INSTANCE attributes into one vertex buffer if
necessary due to hardware constraints.
sync etna driver to 06c1bc8
sync etna driver to cec463b
sync etna driver to 7a68324
fbdev: get rid of want_fence
sync etna driver to 31f10de
sync etna driver to c209f5c
fbdev_etna: use bo object for framebuffer
sync etna driver to c78f82f