arm/dt: msm8974: Add msm bus scaling support for SDCC

The SDCC data transfer (system-memory to card and vice-versa)
    throughput depend on the system bus frequency. The msm bus
    driver allows clients to vote for bus frequency according
    to the throughput requirements of the client.
    The SDCC host on msm8974 can support all UHS-I and HS200
    bus speed modes with following throughput values.
    SDR12   - 13MBps
    SDR25   - 26MBps
    SDR50   - 52MBps
    SDR104  - 104MBps
    HS200   - 208MBps

This reverts commit e945c9b6791a971ed50603a0cd53035469496c39
adding fb50f7f085c4b3bf7d8853f965ab8797579951 back into the
tree.

Change-Id: Ie79805e79382e5c5b974ed5ab144438ed22f0e30
Signed-off-by: Sridhar Parasuram <sridhar@codeaurora.org>