Revert "usb: musb: fix pm_runtime mismatch"

This patch introduced a power consumption regression:
My phone currently has about 80% battery remaining after 10 hours in
idle mode, with the patch reverted it has about 90% after that period.

As I don't know how to fix this properly revert it for now.

This reverts commit 7f697eef88da534a2fb8f3a75cd8e9ee5b7c1a56.

Change-Id: I418b82be3369177e01b5c678a83c752a8be5c933