dt-bindings: mfd: update dlg,da9063.yaml reference

Changeset 441613662db7 ("dt-bindings: mfd: Convert da9063 to yaml")
renamed: Documentation/devicetree/bindings/mfd/da9063.txt
to: Documentation/devicetree/bindings/mfd/dlg,da9063.yaml.

Update its cross-reference accordingly.

Fixes: 441613662db7 ("dt-bindings: mfd: Convert da9063 to yaml")
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/da459164d166d994b06f9ce8bf3a2108ccd0abd5.1656234456.git.mchehab@kernel.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>