ext_tile: add 2 tile encoding modes

Added 2 tile encoding modes:
TILE_NORMAL mode supports the large-scale tile coding up to 1024 x 1024
tiles;
TILE_VR mode supports the large-scale tile coding and also the decoding
of a single tile.

TILE_NORMAL mode allows the non-vr content to be encoded in multiple tiles
without using the coding tool that are designed for vr applications.

Change-Id: Id804806a1bbcb916b7f5dc7e2c5509d88f3defcb