drm/msm/dsi-staging: fix dsi clock voting for dsi-1 only panel

Current design treats clock controller index as an index of clock
configuration inside clock manager structure. For dsi-1 only case
controller index is 1, but clock configuration is stored at index 0.
Patch adds mapping inside clock manager to match dsi controller
indexes with correct core and link clock configurations.

Change-Id: Ie3a467d87f81d9f0b085cc0ab6156c65b5bb8e27
Signed-off-by: Alexander Beykun <abeykun@codeaurora.org>