sound: usb: Fix sending disconnect notification to client

Client's sockaddress related params are not cached but pointer to
sockaddress is cached on receiving request from client. Client's
sockaddress pointer is valid only when request related callback
is called from QMI framework. Due to invalid sockaddress param
USB headset disconnect notification to client is failing. There is
unhandle page fault seen when client is sending more request when
USB headset is already disconnected. Hence fix this issue by storing
sockaddress related params within driver, and use it while sending
unsolicited message to client using qmi_send_indication() i.e. USB
headset disconnect notification.

Change-Id: I569f6aaba9063f3153276bdd4e436644b056cef0
Signed-off-by: Mayank Rana <mrana@codeaurora.org>