PCI: qcom: Indicate broken L1SS exit during resume from system suspend

Qcom PCIe RCs can successfully exit from L1SS during OS runtime. However,
during system suspend, the Qcom PCIe RC driver may remove all resource
votes and turn off the PHY to maximize power savings.

Consequently, when the host is in system suspend with the link in L1SS and
the endpoint asserts CLKREQ#, the RC driver must restore the PHY and enable
the REFCLK. This recovery process causes the L1SS exit latency time to be
exceeded (roughly L10_REFCLK_ON + T_COMMONMODE). If the RC driver were to
retain all votes during suspend, L1SS exit would succeed without issue but
at the expense of higher power consumption.

When the host fails to move the link from L1SS to L0 within the
L10_REFCLK_ON + T_COMMONMODE time, the endpoint may treat it as a fatal
condition and trigger Link Down (LDn) during resume. This LDn results in a
reset that destroys the internal device state.

To ensure that the client drivers can properly handle this scenario, let
them know about this platform limitation by setting the
'pci_host_bridge::broken_l1ss_resume' flag.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260519-l1ss-fix-v2-3-b2c3a4bdeb15@oss.qualcomm.com

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