score: normalize global variables exported by vmlinux.lds

Generate mandatory global variables _sdata in file vmlinux.lds.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/score/kernel/vmlinux.lds.S

@@ -49,6 +49,7 @@ SECTIONS
 	}
 
 	. = ALIGN(16);
+	_sdata =  .;			/* Start of data section */
 	RODATA
 
 	EXCEPTION_TABLE(16)