input: qcom-hv-haptics: check FIFO fill status before stopping play

Check the FIFO real time fill status and only stop FIFO playing in
FIFO empty interrupt handler after confirming all FIFO samples have
been played.

Change-Id: I634f424c960893e22456734f30ae28f5030ca9e1
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>