target: don't free working areas during 'configure -chain-position'

target: don't free working areas during 'configure -chain-position'

Since commit ef1cfb23947b ("Duane Ellis: "target as an [tcl]
object" feature.") merged in 2008, the commands:
	$target_name configure -chain-position ...
	target create ... -chain-position ...
cause the allocated working area to be freed.

There is no reason for this, it is probably caused by an incorrect
copy/paste from the author.

Drop the call to target_free_all_working_areas().

Change-Id: I61a9303afe7fee6953669218330635c0b965b20d
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8825
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>
Tested-by: jenkins