dt-bindings: arm: Add support for DSB element size

Add property "qcom,dsb-elem-size" to support DSB(Discrete Single
Bit) element for TPDM. The associated aggregator will read this
size before it is enabled. DSB element size currently only
supports 32-bit and 64-bit.

Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/1695882586-10306-3-git-send-email-quic_taozha@quicinc.com