drm/i915/glk: Fix DSI enable I/O sequence

drm/i915/glk: Fix DSI enable I/O sequence

One of the if statement covers the next line in enable I/O sequence.
This patch correct the same by adding error message.

Fixes: 4644848369c0 ("drm/i915/glk: Add MIPIIO Enable/disable sequence")
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1488393082-30660-1-git-send-email-madhav.chauhan@intel.com