msm: lpm_levels: fix driver compilation issue

Assigning an unsinged long value to unsinged int is not
correct and it cause driver compilation failure. Fix by
assigning a proper value.

Change-Id: Ia8d214425c3ba07006e748bc74365da6bc22f224
Signed-off-by: Murali Nalajala <mnalajal@codeaurora.org>