arm64: dts: renesas: spider: Move aliases and chosen

The serial console and serial debug ports on Spider are located on the
CPU board.  Hence move the aliases and chosen nodes containing serial
port configuration from the main Spider DTS file to the DTS file that
describes the CPU board.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/c03500bb10eae10caeb3f4f97bc979eeee6cce75.1663167551.git.geert+renesas@glider.be