iio-monitor: Fix memory leaks
iio-monitor: Fix memory leaks

 * char2Chtype() allocates memory which needs to be freed with freeChtype().
 * getString() allocates memory which needs to be freed with freeChar().

Signed-off-by: Lars-Peter Clausen <3318dc5ce3e4fb7c28a0b841b6801c884e1d0896@metafoo.de>

analogdevicesinc/libiio,analogdevicesinc/libiio,gburca/libiio,gburca/libiio,analogdevicesinc/libiio,gburca/libiio,analogdevicesinc/libiio