mb/starlabs/starbook/adl: Set RP9 detection timeout to 50ms

Certain SSDs are not detected in the default time window, so
change this to 50ms to allow these SSDs to be detected.

Change-Id: I60e66096ef9ea0146a1bc72c5c74234353509439
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81398
Reviewed-by: Martin L Roth <gaumless@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/starlabs/starbook/variants/adl/devicetree.cb

@@ -115,6 +115,7 @@ chip soc/intel/alderlake
 				.clk_src			= 1,
 				.clk_req			= 1,
 				.flags				= PCIE_RP_LTR | PCIE_RP_AER,
+				.pcie_rp_detect_timeout_ms	= 50,
 
 			}"
 			smbios_slot_desc			"SlotTypeM2Socket3"