drm: replace bitmap_weight with bitmap_empty where appropriate

drm: replace bitmap_weight with bitmap_empty where appropriate

smp_request_block() in drivers/gpu/drm/msm/disp/mdp5/mdp5_smp.c calls
bitmap_weight() to check if any bit of a given bitmap is set. It's
better to use bitmap_empty() in that case because bitmap_empty() stops
traversing the bitmap as soon as it finds first set bit, while
bitmap_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220210224933.379149-9-yury.norov@gmail.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>