ARM64: dts: amlogic: use generic bus node names

The DT spec recommends that node-names have generic names like "bus".
Fix that in the Amlogic DTs, while leaving the label names to have more
SoC-specific names that match with the HW documentation.

Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>