ppp: make the patches apply correctly again

This fixes a compile problem recently introduced by me.

Fixes: f40fd43ab2f ("ppp: fix compile warning")
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

package/network/services/ppp/patches/500-add-pptp-plugin.patch

@@ -1064,7 +1064,7 @@
 +			   struct in_addr localbind);
 --- /dev/null
 +++ b/pppd/plugins/pptp/pptp_ctrl.c
-@@ -0,0 +1,1077 @@
+@@ -0,0 +1,1078 @@
 +/* pptp_ctrl.c ... handle PPTP control connection.
 + *                 C. Scott Ananian <cananian@alumni.princeton.edu>
 + *