input: qcom-hv-haptics: Add LRA frequency calibration interfaces

Add interfaces to run calibration sequence and read out the closed
loop LRA frequency. With this change, the closed loop LRA frequency
can be read out using following commands:

    echo 1 > /sys/class/qcom-haptics/lra_calibration
    cat /sys/class/qcom-haptics/lra_frequency_hz

Meanwhile, correct the setting for direct play, it expects a 8-bit
value to represent the proportion of vmax instead of the actual vmax
voltage.

Change-Id: I9f3bfb978240ca853446dee4877d6ece4b465058
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>