dt-bindings: arm: aspeed: add IBM SBP1 board

Document the new compatibles used on IBM SBP1.

Signed-off-by: Naresh Solanki <naresh.solanki@9elements.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20241104092220.2268805-1-naresh.solanki@9elements.com
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>

Author: nsolanki22

Documentation/devicetree/bindings/arm/aspeed/aspeed.yaml

@@ -92,6 +92,7 @@ properties:
               - ibm,everest-bmc
               - ibm,fuji-bmc
               - ibm,rainier-bmc
+              - ibm,sbp1-bmc
               - ibm,system1-bmc
               - ibm,tacoma-bmc
               - inventec,starscream-bmc