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/arm/include/asm/spl.h b/arch/arm/include/asm/spl.h
index 62011aa..2b7218e 100644
--- a/arch/arm/include/asm/spl.h
+++ b/arch/arm/include/asm/spl.h
@@ -27,7 +27,7 @@
 #include <asm/arch/spl.h>
 
 /* Linker symbols. */
-extern char __bss_start[], __bss_end__[];
+extern char __bss_start[], __bss_end[];
 
 extern gd_t gdata;