replace last __bss_end__ occurrences with __bss_end

Simon Glass' commit 3929fb0a141530551b3fce15ee08629f80d5ef2a,
which changed all occurrences of __bss__end__ into __bss_end,
left behind some untouched __bss_end__ occurrences in all 33
u-boot.lds.debug files, in board/mousse/u-boot.lds.ram and
in board/mousse/u-boot.lds.rom. These are replaced here.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/board/stx/stxxtc/u-boot.lds.debug b/board/stx/stxxtc/u-boot.lds.debug
index e1fe052..5f74337 100644
--- a/board/stx/stxxtc/u-boot.lds.debug
+++ b/board/stx/stxxtc/u-boot.lds.debug
@@ -132,6 +132,6 @@
    *(.bss)
    *(COMMON)
   }
-  __bss_end__ = . ;
+  __bss_end = . ;
   PROVIDE (end = .);
 }