drm/msm/dpu: simplify clocks handling

DPU driver contains code to parse clock items from device tree into
special data struct and then enable/disable/set rate for the clocks
using that data struct. However the DPU driver itself uses only parsing
and enabling/disabling part (the rate setting is used by DP driver).

Move this implementation to the DP driver (which actually uses rate
setting) and replace hand-coded enable/disable/get loops in the DPU
with the respective clk_bulk operations. Put operation is removed
completely because, it is handled using devres instead.

DP implementation is unchanged for now.

Tested-by: Jessica Zhang <quic_jesszhan@quicinc.com> # RB3 (sdm845) and RB5  (qrb5165)
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220217055529.499829-2-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>