TinyCAN: Fix sending and receiving

This probably broke somewhere in the Qt5 -> Qt6 conversion,
likely because some default configuration parameters changed.

It is important to start the device after all configuration
parameters, including bitrate has been set. Therfore move the
corresponding code block to the correct section.

Tested with a Tiny-CAN I-XL (FD) adapter under Linux.

[ChangeLog][CAN][TinyCAN] Fixed that the TinyCAN plugin did
not send or receive.

Pick-to: 6.12 6.11 6.10 6.8
Fixes: QTBUG-111551
Change-Id: I95601f853cb48fe0f81120d867a2cbaa16c24c8c
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>