devicetree: deprecate DT_DMAS_LABEL APIs

Mark all variants of the DT_DMAS_LABEL APIs:
* DT_DMAS_LABEL_BY_IDX
* DT_DMAS_LABEL_BY_NAME
* DT_INST_DMAS_LABEL_BY_IDX
* DT_INST_DMAS_LABEL_BY_NAME

As deprecated in favor of utilizing:

* DT_DMAS_CTLR_BY_IDX
* DT_DMAS_CTLR_BY_NAME
* DT_DMAS_CTLR
* DT_INST_DMAS_CTLR_BY_IDX
* DT_INST_DMAS_CTLR_BY_NAME
* DT_INST_DMAS_CTLR

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>