drm/msm/dpu: guard ctl irq callback register/unregister

drm/msm/dpu: guard ctl irq callback register/unregister

CTLs on older qualcomm SOCs like msm8953 and msm8996 has not got interrupts,
so better to skip CTL irq callback register/unregister
make dpu_ctl_cfg be able to define without intr_start.

Signed-off-by: Barnabás Czémán <trabarni@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/596854/
Link: https://lore.kernel.org/r/20240509-ctl_irq-v1-1-9433f2da9dc7@gmail.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>