docs: vendor-ibm-astlpc: References as a numbered list

Make it easier to distinguish what text is which document at a glance.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: Ifdd69d9e3af3706c044e374984337609f9d70dde
diff --git a/docs/bindings/vendor-ibm-astlpc.md b/docs/bindings/vendor-ibm-astlpc.md
index 1da144c..626d5f3 100644
--- a/docs/bindings/vendor-ibm-astlpc.md
+++ b/docs/bindings/vendor-ibm-astlpc.md
@@ -10,15 +10,15 @@
 The following referenced documents are indispensable for the application of
 this document.
 
-DMTF DSP0236, Management Component Transport Protocol (MCTP) Base Specification
-1.0,  
+1. DMTF DSP0236, Management Component Transport Protocol (MCTP) Base
+Specification 1.0,  
 http://www.dmtf.org/standards/published_documents/DSP0236_1.0.pdf
 
-Intel (R) Low Pin Count (LPC) Interface Specification 1.1,  
+2. Intel (R) Low Pin Count (LPC) Interface Specification 1.1,  
 https://www.intel.com/content/dam/www/program/design/us/en/documents/low-pin-count-interface-specification.pdf
 
-IPMI Consortium, Intelligent Platform Management Interface Specification, v1.5
-Revision 1.1 February 20, 2002,  
+3. IPMI Consortium, Intelligent Platform Management Interface Specification,
+v1.5 Revision 1.1 February 20, 2002,  
 http://download.intel.com/design/servers/ipmi/IPMIv1_5rev1_1.pdf
 
 ## Definitions