drm/i915: Add some curly braces

drm/i915: Add some curly braces

intel_enable_pipe() looks rather confusing when one side doesn't have
the curly braces, and the other one does. And what's even worse,
there's another if-else inside the braceless side. Let's put braces
around it to make it clear which branch goes where.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470418894-1249-1-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>