arm: make __image_copy_{start, end} compiler-generated

This change is only done where needed: some linker
scripts may contain __image_copy_{start,end} yet
remain unchanged.

Also, __image_copy_end needs its own section; putting
it in relocation sections changes their flags and makes
relocation break.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Tested-by: Lubomir Popov <lpopov@mm-sol.com>
Tested-by: Jeroen Hofstee <jeroen@myspectrum.nl>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
diff --git a/board/actux3/u-boot.lds b/board/actux3/u-boot.lds
index b7d29b4..9d43e95 100644
--- a/board/actux3/u-boot.lds
+++ b/board/actux3/u-boot.lds
@@ -30,6 +30,7 @@
 
 	. = ALIGN (4);
 	.text : {
+		*(.__image_copy_start)
 		arch/arm/cpu/ixp/start.o(.text*)
 		net/libnet.o(.text*)
 		board/actux3/libactux3.o(.text*)
@@ -62,7 +63,10 @@
 
 	. = ALIGN (4);
 
-	__image_copy_end = .;
+	.image_copy_end :
+	{
+		*(.__image_copy_end)
+	}
 
 	.rel.dyn : {
 		__rel_dyn_start = .;