usb: gadget: gsi: Kick state machine with MESSAGE_PACKET_FILTER for RNDIS

commit <5b42bd74> ("usb: gadget: gsi: Optimize TRB's buffer
allocation functionality") is kicking ipa_work_handler state
machine as part of set_alt() for RNDIS function which results
into giving max_xfer_size_bytes_to_host value as zero as
RNDIS_INIT_MSG from host may not have received here. This results
into low throughput due to device is sending more than accepted
aggregated bytes as part of one USB transfer to host. Fix this
issue by delaying RNDIS IPA initialization till MESSAGE_PACKET_FILTER
is received from host which makes sure that proper aggregation
parameters are passed to IPA driver to configure hardware
accerlerated path.

For non-rndis tethered interface, ipa_usb_notify_cb() posts EVT_CONNECTED
to enable IPA GSI data path (i.e. calling ipa_data_path_enable() API).

CRs-Fixed: 1065003
Change-Id: I4ce62745c82b4488cb1370248ab64951497493cd
Signed-off-by: Mayank Rana <mrana@codeaurora.org>