usb: gadget: qdss: Add error log with set_alt failure cases

This change adds error logging to qdss_set_alt() to identify
possible reason for seeing failure in some of cases.

Change-Id: I6a0252ae7d29cc8be037b4fe5e9147e9835d3113
Signed-off-by: Mayank Rana <mrana@codeaurora.org>