drm/msm/dpu: Update function parameter documentation

dpu_core_irq_callback_handler() function comments seem to have become
stale and emit a warning:

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c:147:
warning: Function parameter or member 'dpu_kms' not described in 'dpu_core_irq_callback_handler'
drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c:147:
warning: Excess function parameter 'arg' description in 'dpu_core_irq_callback_handler'

Fix by updating the documentation

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Link: https://lore.kernel.org/r/20220210114106.290669-3-vkoul@kernel.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>