USB: msm72k_otg: Fix USB LPM issue during system suspend

Runtime PM ops are used to put USB into LPM and get it out of LPM.
During system suspend, runtime PM is disabled. Hence connecting USB
cable doesn't get USB out of LPM. Fix this issue, by checking runtime PM
availability and based on it, use direct driver's resume function or
runtime PM resume function.

CRs-Fixed: 358239
Change-Id: I6dfe10a245654c8191eb4fce2f5ac33c95b043a2
Signed-off-by: Chiranjeevi Velempati <cvelempa@codeaurora.org>