adreno/DRM: Get clock rate list from pwrlevel-bins

For Adreno 5 driver under DRM framework, use qcom,gpu-pwrlevel-bins
to get the clock rate list. The driver for older GPU version is
still using qcom,gpu-pwrlevels.

Change-Id: Ic9ed0164ef54f8d318970df59720e88b3f277e7f
Signed-off-by: Kasin Li <donglil@codeaurora.org>