Does not support multiple --driver with the same driver

[ensc]

Describe the bug

When trying to start smuview with multiple devices of the same type, only the first one is instanciated.

E.g.

smuview --driver etommens_etm_xxxxp:conn=`readlink -f /dev/ttyPWR0` \
        --driver etommens_etm_xxxxp:conn=`readlink -f /dev/ttyPWR1`

will create only a window for the first device.

Seems to be caused by

smuview/src/devicemanager.cpp

Line 125 in a5ffb66

it = user_drvs_name_opts.upper_bound(it->first)) {

To Reproduce
Steps to reproduce the behavior:

1. Start smuview with multiple --driver options which specify different instances of the same device type

Expected behavior

every device should appear in smuview

Enviroment (please complete the following information):

• SmuView rev a5ffb66
• Fedora 38