dt-bindings: rtc: imxdi: Improve the bindings text

dt-bindings: rtc: imxdi: Improve the bindings text

Improve the bindings text by doing the following changes:

- Remove the i.MX53 reference, as the RTC on i.MX53 is a different hardware
- Add 'clocks' to the list of required properties
- Explain that the optional security violation irq is the second entry
- Use the real unit address and irq numbers for i.MX25

Signed-off-by: Fabio Estevam <[email protected]>
Acked-by: Juergen Borleis <[email protected]>
Acked-by: Rob Herring <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>