Add support for EP_AGORA

Author: Chris Trowbridge

README.md

@@ -19,6 +19,7 @@ ST NUCLEO_F429ZI                  | Ethernet          | Internal Flash
 ST NUCLEO_F411RE                  | Wi-Fi ESP8266     | SD card                 |
 Ublox UBLOX_EVK_ODIN_W2           | Wi-Fi             | SD card                 |
 ST DISCO_L475VG_IOT01A            | Wi-Fi             | QSPIF                   |
+Embedded Planet Agora             | Cellular          | SPIF                    | Build-only
 
 Build-only = This target is currently verified only via compilation, and is not verified at runtime.