input: qcom-hv-haptics: config interrupt in haptics_set_fifo()

Currently, haptics_fifo_empty_irq_config() uses a mutex lock and it's
called from playback() of input framework which is from an atomic
context. Fix this by moving it out of haptics_playback() and call it
from haptics_set_fifo() which gets eventually called in upload().

With this change, the irq_lock mutex is no longer needed because all
the calling paths of haptics_fifo_empty_irq_config() have been protected
by the mutex lock defined in haptics_play_info structure, hence remove
it.

Change-Id: I4e4d353f8427fb279fd3f4d6a28737acbdb22a0a
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>