vfs: Make __vfs_write() static

__vfs_write() was unexported, and removed from <linux/fs.h>, but
forgotten to be made static.

Fixes: eb031849 ("fs: unexport __vfs_read/__vfs_write")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/read_write.c

@@ -478,8 +478,8 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
 	return ret;
 }
 
-ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
-		    loff_t *pos)
+static ssize_t __vfs_write(struct file *file, const char __user *p,
+			   size_t count, loff_t *pos)
 {
 	if (file->f_op->write)
 		return file->f_op->write(file, p, count, pos);