media: camss: Do not attach an already attached power domain on MSM8916 platform

The change to dynamically allocated power domains neglected a case of
CAMSS on MSM8916 platform, where a single VFE power domain is neither
attached, linked or managed in runtime in any way explicitly.

This is a special case and it shall be kept as is, because the power
domain management is done outside of the driver, and it's very different
in comparison to all other platforms supported by CAMSS.

Fixes: 6b1814e2 ("media: camss: Allocate power domain resources dynamically")
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>