In QMI new server notification we enable the NGD however during
delete server notification we do not disable the NGD.

This can lead to multiple instances of NGD being enabled, so make
sure that we disable NGD in delete server callback to fix this issue!

Fixes: 917809e2 ("slimbus: ngd: Add qcom SLIMBus NGD driver")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200925095520.27316-4-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>