soc: qcom: qmi_interface: Add send timeout helper

Add an api for clients to set the send timeout of the underlying qrtr
socket. QMI sets this timeout to 10 seconds by default but this is too
long for some clients in critical paths.

Change-Id: I4c892a2f034c87b6bf2f71664369140910e72383
Signed-off-by: Chris Lew <clew@codeaurora.org>