Local backend: Close opened devices when exiting
Local backend: Close opened devices when exiting

In the case where the application calls iio_context_destroy() without
first freeing any iio_buffer previously created, the DMA will still
be enabled, and might cause unexpected issues the next time the
application is launched (as some attributes cannot be written if the
DMA is enabled).

Signed-off-by: Paul Cercueil <73d292422978d45c9eeef455bb1b24a0db453722@analog.com>

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