Revert "Revert "UPSTREAM: mmc: dw_mmc: correct the calculation for CLKDIV""

Revert "Revert "UPSTREAM: mmc: dw_mmc: correct the calculation for CLKDIV""

This reverts commit f786fcc8d52e5a7d15a90cf266f2ac1d40f54a5e

Cannot reproduce "won't boot" with "normal" FW versions. See bug for details.

Change-Id: Ibb2730ecef525831883ff26bc04c72a55f47f06d
Reviewed-on: https://gerrit.chromium.org/gerrit/46128
Reviewed-by: Grant Grundler <grundler@chromium.org>
Tested-by: Grant Grundler <grundler@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Commit-Queue: Paul Stewart <pstew@chromium.org>