OMAP: DSS2: DSI: Remove CIO LDO status check

CIO LDO status check seems to be broken on OMAP3630+ chips, and it's
also quite unclear what LDO status actually tells and when its status
changes.

This patch removes the whole check on the grounds that if there's a
problem with the LDO, we should anyway catch the problem as we check the
CIO power state and CIO reset status.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>