Set latch-ck to 1 for mmc0

- DVT boards have trouble flashing, due to CRC errors. These seem to be
tuning related, as naively copying the calculated tuning from LK works
(but slowly, so we don't actually do this.)
- The Linux driver documents the latch-ck parameter, and indicates that
this helps to resolve CRC errors. Enabling this lets flashing work on
DVT units.

Change-Id: Ic101e022f661adedccfc3a2b9b25489671bbb1ca
1 file changed