dump_emit(): use __kernel_write(), not vfs_write()

the caller has already done file_start_write()...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/coredump.c b/fs/coredump.c
index a2856f7..bc3fbcd 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -695,7 +695,7 @@
 	while (nr) {
 		if (dump_interrupted())
 			return 0;
-		n = vfs_write(file, addr, nr, &pos);
+		n = __kernel_write(file, addr, nr, &pos);
 		if (n <= 0)
 			return 0;
 		file->f_pos = pos;