mmc: msm_sdcc: do sampling clock tuning only if card clock is >100MHz

Sampling clock tuning is really not required if card clock is less than
100MHz. This change makes sure that we do tuning only if clock is >100MHz.
In additional, this change also makes sure that if tuning is enabled then
CDR (clock-data recovery) should be enabled only for data read operations.

Change-Id: I5bf26edd8de28d1f53bd258a064475cb0b67b5b5
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>