msm: board-8930: Change min_uV request for Sitar CDC_VDD_CP supply

When using PM8917 with MSM8930, the Sitar CODEC CDC_VPP_CP
supply, PM8917 SMPS 4, is configured to work at only 1.8 V.
Therefore, change the min_uV value that is requested for
CDC_VDD_CP to 1.8 V to accommodate the lower set point.

Change-Id: I48016fa8b281e529935885dfd316ae838fbe16b5
Signed-off-by: David Collins <collinsd@codeaurora.org>