media: qcom: camss: Add an id property to struct resources

In various places in CAMSS we assume a linear set of declared devices
{csiphy0, csiphy1, csiphy2} which currently works for upstream SoCs but for
upcoming SoCs some of the SoC resources will result in a set such as
{csiphy0, csiphy2} which will break the naive for() loops we have.

Introduce an identity property which resource declarations can populate
hence facilitating non-linear resource naming.

Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>