drm/tidss: Fix atomic_flush check

drm/tidss: Fix atomic_flush check

tidss_crtc_atomic_flush() checks if the crtc is enabled, and if not,
returns immediately as there's no reason to do any register changes.

However, the code checks for 'crtc->state->enable', which does not
reflect the actual HW state. We should instead look at the
'crtc->state->active' flag.

This causes the tidss_crtc_atomic_flush() to proceed with the flush even
if the active state is false, which then causes us to hit the
WARN_ON(!crtc->state->event) check.

Fix this by checking the active flag, and while at it, fix the related
debug print which had "active" and "needs modeset" wrong way.

Cc:  <stable@vger.kernel.org>
Fixes: 32a1795f57ee ("drm/tidss: New driver for TI Keystone platform Display SubSystem")
Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com>
Link: https://lore.kernel.org/r/20231109-tidss-probe-v2-10-ac91b5ea35c0@ideasonboard.com
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>