msm: lmh_lite: Fix configurability for LMH software polling

Update the lmh hardware driver to get the polling interval
value from the lmh interface driver, instead of using a local
static variable.

LMH interface driver already exposes debug interface to
configure the interval value.

Change-Id: Ie7d91519f197930ca513b30a671d8f6917d636b0
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>