driver: allocate TS only when needed

TS (Tile Status) keeps track of the clear status per tile.
Thus it is only needed when a resource is bound to a surface,
not for normal textures.
This used to be switched on PIPE_BIND_RENDER_TARGET, but mesa
creates *every* texture with this bit set if possible so we were
wasting some precious consecutive memory here.
etnaviv: prevent false positive about cmd buffer overflow

After a flush, the next start offset may be beyond the end of the
buffer. This is harmless as it makes the next etna_reserve cycle to the next
buffer, but it resulted in a false positive error about a buffer oveflow.
driver: put compiler debug messages behind debug flag

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