[ISDN]: Fix off-by-one errors in isdn_ppp.c

This patch fixes several off by one errors found by the Coverity checker
(ippp_table has ISDN_MAX_CHANNELS elements).

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed