ASoC: doc: dapm: replace "map" with "graph"

DAPM is actually based on a graph, so use this specific term instead of the
more generic "map".

Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://lore.kernel.org/r/20240426-dapm-docs-v2-6-87b07547eb5b@bootlin.com


Signed-off-by: Mark Brown <broonie@kernel.org>