drm/v3d: Use gemfs/THP in BO creation if available

Although Big/Super Pages could appear naturally, it would be quite hard
to have 1MB or 64KB allocated contiguously naturally. Therefore, we can
force the creation of large pages allocated contiguously by using a
mountpoint with "huge=within_size" enabled.

Therefore, as V3D has a mountpoint with "huge=within_size" (if user has
THP enabled), use this mountpoint for BO creation if available. This
will allow us to create large pages allocated contiguously and make use
of Big/Super Pages.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923141348.2422499-10-mcanal@igalia.com