um: take ubd_user.h to its users...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/arch/um/include/shared/ubd_user.h b/arch/um/drivers/ubd_user.h
similarity index 100%
rename from arch/um/include/shared/ubd_user.h
rename to arch/um/drivers/ubd_user.h