msm: lmh_lite: check intensity value before enabling interrupt

Update the driver to check the last read intensity
value for all sensors before enabling the interrupt.
Also clear the last read value before getting the
intensity value from trustzone. This will cover the
cases, where the trustzone read errored out.

Change-Id: Iac22078c0ba92704e2448670248e99880e133d08
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>