Revert "usb: dwc3: Reset num_trbs after skipping"

This reverts commit 9c423fd8.

This is a preparation change for merging android-4.19.57 into
msm-4.19 branch.

Reverted due to BootTimeRunner regression.

Change-Id: I0ff19966bd09d7947a41aed9dec80058c57aafbc
Signed-off-by: Ivaylo Georgiev <irgeorgiev@codeaurora.org>