s390: remove no-op macro VMLINUX_SYMBOL()

VMLINUX_SYMBOL() is no-op unless CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
is defined.  It has ever been selected only by BLACKFIN and METAG.
VMLINUX_SYMBOL() is unneeded for s390-specific code.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/vmlinux.lds.S

@@ -82,10 +82,10 @@ SECTIONS
 
 	. = ALIGN(PAGE_SIZE);
 	.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
-		VMLINUX_SYMBOL(_sinittext) = . ;
+		_sinittext = .;
 		INIT_TEXT
 		. = ALIGN(PAGE_SIZE);
-		VMLINUX_SYMBOL(_einittext) = . ;
+		_einittext = .;
 	}
 
 	/*