TMC2209: Support stealthchop

[wakass]

The 2209 does support stealthchop, so the following line should probably not force it off. Enabling it manually leads to no problems on my end.

Plugins_motor/trinamic.h

Line 58 in 531fae8

#define TMC_STEALTHCHOP 0 // not supported

On a side note: Not sure what a sane default value for this variable is. I would tend to enabling it by default (unless not supported), also in part because the noises my motors made in coolstep mode was quite brutal (although this could be due to some other settings in combination)

[terjeio]

Oops, it is the 2660 that does not support StealthChop - will fix.
What the default for this and other variables should be I do not know, it seems to me that it requires deep knowledge of how the drivers work. I do not have that.

BTW default mode was changed to CoolStep a while back due to user feedback.