platform/x86: toshiba_acpi: Fix defined but not used build warnings

Fix a build warning in toshiba_acpi.c when CONFIG_PROC_FS is not enabled
by marking the unused function as __maybe_unused.

../drivers/platform/x86/toshiba_acpi.c:1685:12: warning: 'version_proc_show' defined but not used [-Wunused-function]
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Azael Avalos <coproscefalo@gmail.com>
Cc: platform-driver-x86@vger.kernel.org
Cc: Andy Shevchenko <andy@infradead.org>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/toshiba_acpi.c

@@ -34,6 +34,7 @@
 #define TOSHIBA_ACPI_VERSION	"0.24"
 #define PROC_INTERFACE_VERSION	1
 
+#include <linux/compiler.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
@@ -1682,7 +1683,7 @@ static const struct file_operations keys_proc_fops = {
 	.write		= keys_proc_write,
 };
 
-static int version_proc_show(struct seq_file *m, void *v)
+static int __maybe_unused version_proc_show(struct seq_file *m, void *v)
 {
 	seq_printf(m, "driver:                  %s\n", TOSHIBA_ACPI_VERSION);
 	seq_printf(m, "proc_interface:          %d\n", PROC_INTERFACE_VERSION);