docs: supported_devices: add missing 8devices Jalapeno (#2936)

Since the device isn't marked as broken it should be mentioned in the docs as a supported device.

docs/user/supported_devices.rst

@@ -183,6 +183,10 @@ brcm2708-bcm2709
 ipq40xx-generic
 ---------------
 
+* 8devices
+
+  - Jalapeno
+
 * Aruba
 
   - AP-303