board: ti: am335x: Add support for BBE Extended WiFi

The Sancloud BeagleBone Enhanced Extended WiFi (BBE Extended WiFi) has
its own devicetree file and the board can be identified by the 2nd
letter of the config string within the common EEPROM.

Signed-off-by: Paul Barker <paul.barker@sancloud.com>
diff --git a/include/configs/am335x_evm.h b/include/configs/am335x_evm.h
index 746d11b..fd5b209 100644
--- a/include/configs/am335x_evm.h
+++ b/include/configs/am335x_evm.h
@@ -136,6 +136,8 @@
 			"setenv fdtfile am335x-sancloud-bbe.dtb; fi; " \
 		"if test $board_name = BBELITE; then " \
 			"setenv fdtfile am335x-sancloud-bbe-lite.dtb; fi; " \
+		"if test $board_name = BBE_EX_WIFI; then " \
+			"setenv fdtfile am335x-sancloud-bbe-extended-wifi.dtb; fi; " \
 		"if test $board_name = A33515BB; then " \
 			"setenv fdtfile am335x-evm.dtb; fi; " \
 		"if test $board_name = A335X_SK; then " \