input: qcom-hv-haptics: Add debugfs files for more brake settings

Add debugfs parameters per effect to enable brake and brake sine
waveform gain setting. Meanwhile, change to print the FIFO samples
with signed magnitude values so that they can be used offline to
plot pattern waveform.

Change-Id: Iaeeeedbba570333c8c4fa9793e2b4e9c1b4af09a
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>