module: replace VMLINUX_SYMBOL_STR() with __stringify() or string literal

With the special case handling for Blackfin and Metag was removed by
commit 94e58e0ac312 ("export.h: remove code for prefixing symbols with
underscore"), VMLINUX_SYMBOL_STR() is now equivalent to __stringify().

Replace the remaining usages to prepare for the entire removal of
VMLINUX_SYMBOL_STR().

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
diff --git a/kernel/module.c b/kernel/module.c
index b6b3a3c..ba45a84 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1341,14 +1341,12 @@
 	 * locking is necessary -- use preempt_disable() to placate lockdep.
 	 */
 	preempt_disable();
-	if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL,
-			 &crc, true, false)) {
+	if (!find_symbol("module_layout", NULL, &crc, true, false)) {
 		preempt_enable();
 		BUG();
 	}
 	preempt_enable();
-	return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
-			     mod, crc);
+	return check_version(info, "module_layout", mod, crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */