isdn/capi: make reset_ctr op truly optional
isdn/capi: make reset_ctr op truly optional

The CAPI controller operation reset_ctr is marked as optional, and
not all drivers do implement it. Add a check to the kernel CAPI
whether it exists before trying to call it.

Signed-off-by: Tilman Schmidt <dc8b785d67b4628425f4b275427621124af5d812@imap.cc>
Acked-by: Karsten Keil <49f1bb9db9887b2592204b53c4cd2e640734837a@linux-pingi.de>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas