fx2lafw: silence error message in query for channel group's device options
The fx2lafw(4) driver supports mere logic analyzers as well as mixed
signal devices, but does not support channel group specific device
options. Avoid an error message when channel group device options get
queried, the condition is perfectly legal and non-fatal.
How to reproduce:
$ pulseview -d fx2lafw
$ sigrok-cli -d fx2lafw -g Logic --show
projects / libsigrok.git / commit