scsi: ufs: add pre & post status change to clk_scale_notify ops

Some UFS host controller implementation may require vendor specific
configurations before and after changing the UFS controller
clock frequencies. This change adds the support for this.

Change-Id: Id4171ef8786fa6883d9af914dc2a675cb62c6a72
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[venkatg@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
[cang@codeaurora.org: Resolved trivial merge conflicts]
Signed-off-by: Can Guo <cang@codeaurora.org>