Handle 'sk' being NULL in UID-based routing.

Bug: 15413527
Change-Id: Iab1fae9da6053b284591628ef1de878761b137b1
Signed-off-by: Sreeram Ramachandran <sreeram@google.com>
usb: gadget: f_accessory: Enabled Zero Length Packet (ZLP) for acc_write

Accessory connected to Android Device requires
Zero Length Packet (ZLP) to be written when data
transferred out from the Android device are multiples
of wMaxPacketSize (64bytes (Full-Speed) / 512bytes (High-Speed))
to end the transfer.

Change-Id: Ib2c2c0ab98ef9afa10e74a720142deca5c0ed476
Signed-off-by: Anson Jacob <ansonkuzhumbil@gmail.com>