dt-bindings: serial: 8250: deprecate aspeed, sirq-polarity-sense

This property ties SIRQ polarity to SCU register bits that don't
necessarily have any direct relationship to it; the only use of it was
removed in commit c82bf6e133 ("ARM: aspeed: g5: Do not set sirq
polarity").

Reviewed-by: Joel Stanley <joel@jms.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20210412034712.16778-2-zev@bewilderbeest.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/serial/8250.yaml

@@ -189,6 +189,7 @@ properties:
       offset and bit number to identify how the SIRQ polarity should be
       configured. One possible data source is the LPC/eSPI mode bit. Only
       applicable to aspeed,ast2500-vuart.
+    deprecated: true
 
 required:
   - reg