sparc: leon3: Updates for generic board initialization

Reworked the LEON3 start.S code to call board_init_f function at startup.
Also implemented the relocate_code function in assembly to relocate the
monitor and setup the stack pointer before calling relocated board_init_r.

Add the CONFIG_SYS_GENERIC_BOARD variable to all the LEON3 boards.

Signed-off-by: Francois Retief <fgretief@spaceteq.co.za>
diff --git a/include/configs/gr_xc3s_1500.h b/include/configs/gr_xc3s_1500.h
index 5fb800b..8598ac1 100644
--- a/include/configs/gr_xc3s_1500.h
+++ b/include/configs/gr_xc3s_1500.h
@@ -13,6 +13,8 @@
 #ifndef __CONFIG_H__
 #define __CONFIG_H__
 
+#define CONFIG_SYS_GENERIC_BOARD
+
 /*
  * High Level Configuration Options
  * (easy to change)