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/mpc5xxx/u-boot-spl.lds b/arch/powerpc/cpu/mpc5xxx/u-boot-spl.lds
index cab9b92..0500739 100644
--- a/arch/powerpc/cpu/mpc5xxx/u-boot-spl.lds
+++ b/arch/powerpc/cpu/mpc5xxx/u-boot-spl.lds
@@ -52,6 +52,6 @@
 		__bss_start = .;
 		*(.bss*)
 		. = ALIGN(4);
-		__bss_end__ = .;
+		__bss_end = .;
 	} > sdram
 }