soc: qcom: hab: run the dispatcher's tasklet w/ high priority

HAB uses tasklets as the bottom half to receive message from the
remote side. Even when the whole system is overloaded, HAB clients
(e.g., audio, display, gfx) still expect low latency for good user
experience. So here, tasklet_hi_schedule() is used.

Change-Id: I0b8ed281f090e9c251eb62fe5e78900ea2e9dc8d
Signed-off-by: Yong Ding <yongding@codeaurora.org>