sparc64: Increase size of boot string to 1024 bytes

This is the longest boot string that silo supports.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: Bob Picco <bob.picco@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

(cherry picked from commit 1cef94c3)
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

arch/sparc/prom/bootstr_64.c

@@ -14,7 +14,10 @@
  *          the .bss section or it will break things.
  */
 
-#define BARG_LEN  256
+/* We limit BARG_LEN to 1024 because this is the size of the
+ * 'barg_out' command line buffer in the SILO bootloader.
+ */
+#define BARG_LEN 1024
 struct {
 	int bootstr_len;
 	int bootstr_valid;