ARM: dts: aspeed: bletchley: Cleanup redundant nodes

Cleanup following nodes:

1. Remove redundant i2c1 node.
2. Disable in-chip rtc, use battery-backed external rtc (pcf85263)
   instead.

Signed-off-by: Potin Lai <potin.lai@quantatw.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Patrick Williams <patrick@stwcx.xyz>
Link: https://lore.kernel.org/r/20220215163151.32252-11-potin.lai@quantatw.com


Signed-off-by: Joel Stanley <joel@jms.id.au>