[POWERPC] Move prototype for find_udbg_vterm() into a header file

Move the prototype for find_udbg_vterm() into pseries.h, removing
it from setup.c.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/pseries/setup.c

@@ -76,9 +76,6 @@
 #define DBG(fmt...)
 #endif
 
-/* move those away to a .h */
-extern void find_udbg_vterm(void);
-
 int fwnmi_active;  /* TRUE if an FWNMI handler is present */
 
 static void pseries_shared_idle_sleep(void);