configure: make device drivers depend on "serial comm" not libserialport

configure: make device drivers depend on "serial comm" not libserialport

A previous commit introduced the more generic "have serial communication"
condition, and adjusted the list of available libsigrok dependencies.

This commit adjusts device driver dependency declarations. This allows
to build e.g. DMM drivers in the presence of RFCOMM support but in the
absence of libserialport, because any of several optional external libs
can make serial communication available.