dccp: fix warning in net/dccp/options.c

this warning:

  net/dccp/options.c: In function ‘dccp_parse_options’:
  net/dccp/options.c:67: warning: ‘value’ may be used uninitialized in this function

is a bogus GCC warning. The compiler does not recognize the relation
between "value" and "mandatory" variables: the code flow can ever reach
the "out_invalid_option:" label if 'mandatory' is set to 1, and when
'mandatory' is non-zero, we'll always have 'value' initialized.

Help out the compiler by annotating the variable.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dccp/options.c

@@ -67,7 +67,7 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
 					(dh->dccph_doff * 4);
 	struct dccp_options_received *opt_recv = &dp->dccps_options_received;
 	unsigned char opt, len;
-	unsigned char *value;
+	unsigned char *uninitialized_var(value);
 	u32 elapsed_time;
 	__be32 opt_val;
 	int rc;