soc: qcom: qmi: Fix NULL pointer access during REMOVE_SERVER event

While processing REMOVE_SERVER event, the destination address in a
client handle is accessed without any NULL pointer validation. This
leads to a crash if the REMOVE_SERVER event is handled when the client
is in the middle of initialization and is not connected to a service.

Validate the destination address in the client handle before accessing
it.

CRs-Fixed: 668684
Change-Id: I17d019a33396311e7b86207309d10c9034ce8544
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>