i965: correct mt->align_h for 2D textures on Skylake

i965: correct mt->align_h for 2D textures on Skylake

In agreement with commit 4ab8d59a23, vertical alignment values are equal to
four times the block height on Gen9+.

v2: add newlines to separate declarations, statments, and comments.

Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Signed-off-by: Nanley Chery <nanley.g.chery@intel.com>