dt/flattree: explicitly pass command line pointer to early_init_dt_scan_chosen

This patch drops the reference to a global 'cmd_line' variable from
early_init_dt_scan_chosen, and instead passes the pointer to the command
line string via the *data argument.  Each architecture does something
slightly different with the initial command line, so it makes sense for
the architecture to be able to specify the variable name.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

arch/mips/kernel/prom.c

@@ -83,7 +83,8 @@ void __init early_init_devtree(void *params)
 	 * device-tree, including the platform type, initrd location and
 	 * size, and more ...
 	 */
-	of_scan_flat_dt(early_init_dt_scan_chosen, NULL);
+	of_scan_flat_dt(early_init_dt_scan_chosen, arcs_cmdline);
+
 
 	/* Scan memory nodes */
 	of_scan_flat_dt(early_init_dt_scan_root, NULL);