Rename some of the tile_offset() functions to aligned_offset() since
they operate on both linear and tiled functions. And we'll include
_plane_ in the name of all the variants that take a plane state.
Should make it more clear which function to use where.

v2: Pimp the patch subject a bit (José)
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180907152413.15761-2-ville.syrjala@linux.intel.com