disp: msm: dp: send dp hpd notification from attention_work

The hpd notification is skipped in connect_work if there is an
attention_work pending. So, the notification has to be sent in
attention_work.

Some dongles issue multiple attention events with LINK_STATUS_UPDATED
while the connect_work is in progress. So, once the link training
is successfully completed the LINK_STATUS_UPDATED attention event is
considered handled and the attention_work scheduled to execute after
the connect_work will return early without handling the
hpd_notification cases.

This change will ensure the hpd_notification is sent from
attention_work in such cases.

Change-Id: I5ef6781354b80842d2a6f44360cde25ee6d2b0b7
Signed-off-by: Sankeerth Billakanti <sbillaka@codeaurora.org>