remove all (legacy) "i4b_" prefixes outside of sys/netisdn.
Prefix all card specific driver support files with the basename
of the driver bus attachement file.
Renamed here:
i4b_isic_pcmcia.c -> isic_pcmcia.c
i4b_isic_pcmcia.h -> isic_pcmcia.h
i4b_avm_fritz_pcmcia.c -> isic_pcmcia_avm_fritz.c
i4b_elsa_isdnmc.c -> isic_pcmcia_elsa_isdnmc.c
i4b_elsa_mcall.c -> isic_pcmcia_elsa_mcall.c
i4b_sbspeedstar2.c -> isic_pcmcia_sbspeedstar2.c