input: qcom-hv-haptics: only use 4-byte writes when refilling FIFO

The haptics module supports writing FIFO samples using 4-byte burst
mode as well as 1-byte mode. During FIFO refilling, if a 1-byte write
was used, then the hardware would fill zeros automatically after that
to keep the FIFO data 4-byte aligned. When this happened in the middle
of playing, the hardware inserted 0 values would cause spurs on the
haptics output. To fix this, only use 4-byte burst writes during FIFO
refilling until the end of the play.

Change-Id: I0441942585e0e0d5da62ec4a7123b2763b292739
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>