ARM: dts: aspeed: bletchley: Switch sled numbering to 1-based

Switch sled to 1-based to meet OpenBMC multi-host numbering rule
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/20220215163151.32252-2-potin.lai@quantatw.comSigned-off-by: Joel Stanley <joel@jms.id.au>