drm/i915/fbc: Remove ancient 16k plane stride limit

The 16k max plane stride limit seems to be originally from
i965gm, and no explicit limit has been specified since (g4x+).
So let's assume the max plane stride itself is a suitable limit
also for the more recent FBC hardware.

In fact even for i965gm the max X-tiled stride is also 16k so
technically we don't need the check there either, but let's
keep it there anyway since it's explicitly mentioned in the
spec. Gen2/3 have more strict limits checked separately.

Reviewed-by: Swati Sharma <swati2.sharma@intel.com>
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231003194256.28569-1-ville.syrjala@linux.intel.com