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/mpc8xx/start.S b/arch/powerpc/cpu/mpc8xx/start.S
index ebca3ac..5aa50c5 100644
--- a/arch/powerpc/cpu/mpc8xx/start.S
+++ b/arch/powerpc/cpu/mpc8xx/start.S
@@ -72,7 +72,7 @@
 	GOT_ENTRY(transfer_to_handler)
 
 	GOT_ENTRY(__init_end)
-	GOT_ENTRY(__bss_end__)
+	GOT_ENTRY(__bss_end)
 	GOT_ENTRY(__bss_start)
 	END_GOT
 
@@ -590,7 +590,7 @@
 	 * Now clear BSS segment
 	 */
 	lwz	r3,GOT(__bss_start)
-	lwz	r4,GOT(__bss_end__)
+	lwz	r4,GOT(__bss_end)
 
 	cmplw	0, r3, r4
 	beq	6f