xilinx: Use variable for passing board_name

Use variable which points to DEVICE_TREE by default. The reason for this
change is to enable DTB_RESELECT and MULTI_DTB_FIT where board detection
can be used for change DTB at run time. That's why there must be reference
in board_fit_config_name_match() via variable instead of hardcoding it
which is sufficient for that use case.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>

board/xilinx/common/board.c

@@ -436,11 +436,13 @@ int board_late_init_xilinx(void)
 }
 #endif
 
+static char *board_name = DEVICE_TREE;
+
 int __maybe_unused board_fit_config_name_match(const char *name)
 {
-	debug("%s: Check %s, default %s\n", __func__, name, DEVICE_TREE);
+	debug("%s: Check %s, default %s\n", __func__, name, board_name);
 
-	if (!strcmp(name, DEVICE_TREE))
+	if (!strcmp(name, board_name))
 		return 0;
 
 	return -1;