arm: fix incorrect monitor protection region in FLASH

Monitor protection region in FLASH did not cover .rel.dyn
and .dynsym sections, because it uses __bss_start to compute
monitor_flash_len. Use _end instead.

Add _end to linker scripts for end of u-boot image
Add _end_ofs to all the start.S.

Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>
diff --git a/arch/arm/cpu/arm1136/u-boot.lds b/arch/arm/cpu/arm1136/u-boot.lds
index 1e0e90b..d1e2851 100644
--- a/arch/arm/cpu/arm1136/u-boot.lds
+++ b/arch/arm/cpu/arm1136/u-boot.lds
@@ -72,6 +72,8 @@
 		*(.dynsym)
 	}
 
+	_end = .;
+
 	.bss __rel_dyn_start (OVERLAY) : {
 		__bss_start = .;
 		*(.bss)