dma: rcar-audmapp: add DT support

This patch adds DT support to Audio DMAC peri peri driver.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[horms+renesas@verge.net.au: Do not add trailing blank line to rcar-audmapp.txt]
[horms+renesas@verge.net.au: squashed patch to add NULL terminater to audmapp_of_match]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>