rename _end to __bss_end__

Currently, _end is used for end of BSS section.  We want _end to mean
end of u-boot image, so we rename _end to __bss_end__ first.

Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>
diff --git a/examples/standalone/mips.lds b/examples/standalone/mips.lds
index 63a1c92..68ae217 100644
--- a/examples/standalone/mips.lds
+++ b/examples/standalone/mips.lds
@@ -55,5 +55,5 @@
 	.sbss (NOLOAD) : { *(.sbss) }
 	.bss (NOLOAD)  : { *(.bss) . = ALIGN(4); }
 
-	_end = .;
+	__bss_end__ = .;
 }
diff --git a/examples/standalone/sparc.lds b/examples/standalone/sparc.lds
index 9733daa..7f060b6 100644
--- a/examples/standalone/sparc.lds
+++ b/examples/standalone/sparc.lds
@@ -57,5 +57,5 @@
 	}
 	. = ALIGN(4);
 	__bss_end = .;
-	_end = .;
+	__bss_end__ = .;
 }
diff --git a/examples/standalone/stubs.c b/examples/standalone/stubs.c
index 2d2e709..1379df7 100644
--- a/examples/standalone/stubs.c
+++ b/examples/standalone/stubs.c
@@ -187,14 +187,14 @@
 #include <_exports.h>
 }
 
-extern unsigned long __bss_start, _end;
+extern unsigned long __bss_start, __bss_end__;
 
 void app_startup(char * const *argv)
 {
 	unsigned char * cp = (unsigned char *) &__bss_start;
 
 	/* Zero out BSS */
-	while (cp < (unsigned char *)&_end) {
+	while (cp < (unsigned char *)&__bss_end__) {
 		*cp++ = 0;
 	}