softpipe: raise number of bits used for X coordinate texture lookup

softpipe: raise number of bits used for X coordinate texture lookup

With buffers the addressing is done on a per byte basis and we with
a maximal block size of 16 byte we have to take into acount four more
bits. For simplicity just remove the TEX_TILE_SIZE_LOG2, which is 5 bit.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>