plugins/fmcomms1.c: Add ADC sampl freq to the Save/Restore list

Signed-off-by: Dan Nechita <dan.nechita@analog.com>
plugins/fmcomms1.c: Update DDS widgets after a profile load

Signed-off-by: Dan Nechita <dan.nechita@analog.com>
plugins/fmcomms1.c: Add gain lock option to Save/Restore list

Signed-off-by: Dan Nechita <dan.nechita@analog.com>
plugins/fmcomms1.c: Make gain widgets show the actual set value
 - Adds a progress bar to the spinbutton which at complete updates itself with the value of the attribute that could be set.

Signed-off-by: Dan Nechita <dan.nechita@analog.com>