drm/msm/dpu: simplify DPU's regset32 code

Squash dpu_debugfs_setup_regset32() into dpu_debugfs_create_regset32().
it makes little sense to have separate function to just setup the
structure.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Link: https://lore.kernel.org/r/20211201222633.2476780-8-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>