config: am335x_evm: detect Black Wireless using BWA

BeagleBone Black Wireless is clone of the BeagleBone Black (BBB) with
the Ethernet replaced by a TI wl1835 wireless module.

This board can be indentified by the BWAx value after A335BNLT (BBB)
in the at24 eeprom:
BWAx [aa 55 33 ee 41 33 33 35  42 4e 4c 54 42 57 41 35  |.U3.A335BNLTBWA5|]

http://beagleboard.org/black-wireless
https://github.com/beagleboard/beaglebone-black-wireless

firmware: https://github.com/beagleboard/beaglebone-black-wireless/tree/master/firmware
wl18xx mac address: /proc/device-tree/ocp/ethernet@4a100000/slave@4a100200/mac-address

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
CC: Tom Rini <trini@konsulko.com>
CC: Jason Kridner <jkridner@beagleboard.org>
CC: Will Newton <willn@resin.io>
Reviewed-by: Tom Rini <trini@konsulko.com>

board/ti/am335x/board.c

@@ -651,6 +651,13 @@ int board_late_init(void)
 #ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 	char *name = NULL;
 
+	if (board_is_bone_lt()) {
+		/* BeagleBoard.org BeagleBone Black Wireless: */
+		if (!strncmp(board_ti_get_rev(), "BWA", 3)) {
+			name = "BBBW";
+		}
+	}
+
 	if (board_is_bbg1())
 		name = "BBG1";
 	set_board_info_env(name);

include/configs/am335x_evm.h

@@ -138,6 +138,8 @@
 			"setenv fdtfile am335x-bone.dtb; fi; " \
 		"if test $board_name = A335BNLT; then " \
 			"setenv fdtfile am335x-boneblack.dtb; fi; " \
+		"if test $board_name = BBBW; then " \
+			"setenv fdtfile am335x-boneblack-wireless.dtb; fi; " \
 		"if test $board_name = BBG1; then " \
 			"setenv fdtfile am335x-bonegreen.dtb; fi; " \
 		"if test $board_name = A33515BB; then " \