isdn/gigaset: improve bas_gigaset USB error reporting
isdn/gigaset: improve bas_gigaset USB error reporting

Rephrase some USB error messages to make them clearer and more consistent.
Downgrade some warning messages that may occur during normal operation to
debug messages.

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