dt-bindings: memory-controller: qca,ath79-ddr-controller: Drop consumer from example

dt-bindings: memory-controller: qca,ath79-ddr-controller: Drop consumer from example

Normal practice is examples only show what the binding document defines
and doesn't include consumers in a provider example (or vice-versa). The
"qca,ddr-wb-channel-interrupts" and "qca,ddr-wb-channels" properties are
also not yet documented by a schema, so avoid (not yet enabled) warnings
on them by dropping the interrupt-controller node from the example.

Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20250103212448.2852884-1-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>