dwc3-msm: Don't mark fatal error with IN_L2 for USB cable disconnect case

In some cases, it has been observed that USB PHY is not going into IN_L2
state with USB cable disconnect case. This change marks seeing IN_L2 error
as fatal with USB host mode or USB device bus suspend case only. USB cable
disconnect functionality does power collapse USB controller and PHYs
whereas performs POR sequence with USB cable connect. Hence going into USB
LPM sequence with USB PHY not suspended properly should be no harm.

This change also captures few important registers when IN_L2 error is seen.

CRs-Fixed: 1063744
Change-Id: Ibe5a85ce4c78b7346e8840916f868cf8011e2b92
Signed-off-by: Mayank Rana <mrana@codeaurora.org>