i965/gen9: Pass alignment as function parameter in drm_intel_gem_bo_alloc_internal()

In case of YF/YS tiled buffers libdrm need not know about the tiling
format because these buffers don't have hardware support to be tiled
or detiled through a fenced region. But, libdrm still need to know
about buffer alignment restrictions because kernel uses it when
resolving the relocation.

Mesa uses drm_intel_gem_bo_alloc_for_render() to allocate Yf/Ys buffers.
So, use the passed alignment value in this function to initialize the
align variable in drm_intel_bo. Note that we continue ignoring the
alignment value passed to drm_intel_gem_bo_alloc() to follow the
previous behavior.

V2: Add a condition to avoid allocation from cache. (Ben)
V3: Make no changes in cache allocation strategy. Just update the alignment.
    Update the aperture size estimate including the alignment. (Ben, Chris)
V4: Move aperture size adjustments inside drm_intel_bo_gem_set_in_aperture_size()
    Don't split sentences across the one-line header and the changelog. (Chris)

Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>