PCI: dwc: Add L1 Substates context to ltssm_status of debugfs

PCI: dwc: Add L1 Substates context to ltssm_status of debugfs

DWC core couldn't distinguish LTSSM state among L1.0, L1.1 and L1.2. But
the vendor glue driver may implement additional logic to convey this
information. So add two pseudo definitions for vendor glue drivers to
translate their internal L1 Substates for debugfs to show.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/1765503205-22184-1-git-send-email-shawn.lin@rock-chips.com