usb: f_qdss: Cleanup control interface as no longer in use

Currently, if debug_inface is enabled the list pool allocation is
done for ctrl_write_pool instead of data_write_pool. Therefore
when coresight calls qdss_write function it finds the data_write_pool
empty & since data is populated in ctrl_write_pool, it will return
-EIO. This restricts qdss to work on a composition where ctrl & data
write pool coexists.

Fix this by removing the control interface as it is no longer used.

Change-Id: I2d6368d8f5a1b0ada2634ec682f19bc99551c76c
Signed-off-by: Udipto Goswami <ugoswami@codeaurora.org>