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: I32684fb4b2c05285b40d164ec5df8d1eb8eba114
Signed-off-by: Yong Ding <yongding@codeaurora.org>