usb: ci13xxx_udc: Send CONNECT_EVENT only when pull_up/vbus is enabled

Currently CI13XXX_CONTROLLER_CONNECT_EVENT is being sent from
hw_device_state() API which is being called in different context
like at the time of UDC binding, enabling pull-up when gadget
is enabled. This event is used with different USB core for different
functionality which only required to be enabled when device controller
is enabled. Hence send this event only when pull_up is being enabled
and vbus_session() is being called.

Change-Id: I51deae19f9cb453df3028bffbfdbb593ee36dbc8
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
Signed-off-by: Lena Salman <esalman@codeaurora.org>