drm/i915: Limit plane stride to below TILEOFF.x limit

Limit pre-skl plane stride to below 4k or 8k pixels (depending on
the platform). We do this in order guarantee that TILEOFF/OFFSET.x
does not get too big.

Currently this is not a problem as we align SURF to 4k, and so
TILEOFF/OFFSET only have to deal with a single tile's worth of
pixels. But for async flips we're going to have to bump SURF
alignment to 256k, and thus we can no longer guarantee
TILEOFF/OFFSET.x will stay within acceptable bounds. We can avoid
this by borrowing a trick from the skl+ code and limit the max
plane stride to whatever value we can fit into TILEOFF/OFFSET.x.

The slight downside is that we may end up doing GTT remapping in
a few more cases where previously we did not have to. But since
that will only happen with huge buffers I'm not really concerned
about it.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111163711.12913-3-ville.syrjala@linux.intel.com
Reviewed-by: Karthik B S <karthik.b.s@intel.com>

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