sparc32: fix sparse warning in devices.c

Fix following warning:
devices.c:114:13: warning: symbol 'device_scan' was not declared. Should it be static?

Add prototype to asm/setup.h

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/setup.h

@@ -39,6 +39,9 @@ int sparc_floppy_request_irq(unsigned int irq, irq_handler_t irq_handler);
 /* setup_32.c */
 extern unsigned long cmdline_memory_size;
 
+/* devices.c */
+void __init device_scan(void);
+
 #endif
 
 extern void sun_do_break(void);