Replace __bss_end__ with __bss_end

Note this is a tree-wide change affecting multiple architectures.

At present we use __bss_start, but mostly __bss_end__. This seems
inconsistent and in a number of places __bss_end is used instead.

Change to use __bss_end for the BSS end symbol throughout U-Boot. This
makes it possible to use the asm-generic/sections.h file on all
archs.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc8260/start.S b/arch/powerpc/cpu/mpc8260/start.S
index 3299d72..bd8d7ac 100644
--- a/arch/powerpc/cpu/mpc8260/start.S
+++ b/arch/powerpc/cpu/mpc8260/start.S
@@ -65,7 +65,7 @@
 	GOT_ENTRY(transfer_to_handler)
 
 	GOT_ENTRY(__init_end)
-	GOT_ENTRY(__bss_end__)
+	GOT_ENTRY(__bss_end)
 	GOT_ENTRY(__bss_start)
 #if defined(CONFIG_HYMOD)
 	GOT_ENTRY(environment)
@@ -920,7 +920,7 @@
 	 */
 	lwz	r4,GOT(environment)
 #else
-	lwz	r4,GOT(__bss_end__)
+	lwz	r4,GOT(__bss_end)
 #endif
 
 	cmplw	0, r3, r4