arm: make _end compiler-generated

This prevents references to _end from generating absolute
relocation records.

This change is binary invariant for ARM targets.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 321997c..45febcf 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -32,7 +32,6 @@
 ifndef CONFIG_SYS_GENERIC_BOARD
 obj-y	+= board.o
 endif
-obj-y	+= sections.o
 
 obj-$(CONFIG_OF_LIBFDT) += bootm-fdt.o
 obj-$(CONFIG_CMD_BOOTM) += bootm.o
@@ -43,6 +42,7 @@
 obj-$(CONFIG_SPL_FRAMEWORK) += spl.o
 endif
 
+obj-y	+= sections.o
 ifdef CONFIG_ARM64
 obj-y	+= interrupts_64.o
 else