I know that some people belive that goto's are devil's work
but sometimes (like chaining if/elses for failures) it can
actually simplify the code for a better readability and
improved speed.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

Strings can be expensive to create, all the issues with allocation,
copy of the char members, conversion to UTF-16. QStringLiteral creates
one in compile time.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

Also fixed problem with setup complete signaling after positive
calibration completed