ARM: dts: msm: add bus scale values for bandwidth scaling

Add bus frequency scaling support for multiple gen speeds
based on scaling requests issued by device.

CRs-Fixed: 2479785
Change-Id: Idaadc3a1cc0ca61c139e466f7ee9be9a9106b883
Acked-by: Bhaumik Vasav Bhatt <bbhatt@qti.qualcomm.com>
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>