The variable 'error' in sys_poll() is initialized in declaration to value

zero but in any case is overwritten by successive copyin(), making the
previous initialization useless. Remove this.
As an added bonus this fixes a style(9) bug.

Discussed with:		kib
Approved by:		gnn (mentor)
MFC after:		3 days

sys/kern/sys_generic.c

@@ -1255,7 +1255,7 @@ sys_poll(td, uap)
 	struct pollfd *bits;
 	struct pollfd smallbits[32];
 	struct timeval atv, rtv, ttv;
-	int error = 0, timo;
+	int error, timo;
 	u_int nfds;
 	size_t ni;