isdn/gigaset: correct CAPI voice connection encoding
isdn/gigaset: correct CAPI voice connection encoding

Make the Gigaset CAPI driver select L2_VOICE (AT^SBPR=2) as the
layer 2 encoding for transparent connections, like the ISDN4Linux
variant.  L2_BITSYNC (AT^SBPR=0) mutes internal connections and
distorts external ones.

Impact: bugfix
Signed-off-by: Tilman Schmidt <dc8b785d67b4628425f4b275427621124af5d812@imap.cc>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

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