update README (#735) (#599)

Update README to include pointers to P2P and write combine

Author: kyyalama2

README.md

@@ -221,4 +221,6 @@ Documentation is located throughout this developer kit and the table below conso
 | AFI - Creation Error Codes | [create\_fpga\_image\_error\_codes](hdk/docs/create_fpga_image_error_codes.md) | CLI documentation for managing AFIs |
 | AFI - Power | [FPGA Power, recovering from clock gating](./hdk/docs/afi_power.md) | Helps developers with understanding FPGA power usage, preventing power violations on the F1 instance and recovering from a clock gated slot. |
 | On-premise Development | [Tools, Licenses required for on-premise development](./docs/on_premise_licensing_help.md) | Guidance for developer wanting to develop AFIs from on-premises instead of using the [FPGA Developer AMI](https://aws.amazon.com/marketplace/pp/B06VVYBLZZ) |
+| PCIe Peer-2-Peer     | [P2P](https://github.com/awslabs/aws-fpga-app-notes/blob/master/Using-PCIe-Peer2Peer/README.md) | Guidance on using PCIe P2P |
+| PCIe write combining | [PCIe write combine](https://github.com/awslabs/aws-fpga-app-notes/blob/master/Using-PCIe-Write-Combining/README.md) | Documentation on PCIe write combining for performance improvement |
 | Frequently asked questions | [FAQ](./FAQs.md)| Q/A are added based on developer feedback and common AWS forum questions  |