um: header debriding - sigio.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/shared/sigio.h

@@ -7,7 +7,6 @@
 #define __SIGIO_H__
 
 extern int write_sigio_irq(int fd);
-extern int register_sigio_fd(int fd);
 extern void sigio_lock(void);
 extern void sigio_unlock(void);