PCI: qcom: Advertise Hotplug Slot Capability with no Command Completion support

PCI: qcom: Advertise Hotplug Slot Capability with no Command Completion support

Qcom PCIe Root Ports advertise hotplug capability in hardware, but do not
support hotplug command completion. As a result, the hotplug commands
issued by the pciehp driver never gets completion notification, leading to
repeated timeout warnings and multi-second delays during boot and
suspend/resume.

Commit a54db86ddc153 ("PCI: qcom: Do not advertise hotplug capability for
IPs v2.7.0 and v1.9.0") mistakenly assumed that the Root Ports doesn't
support Hotplug due to timeouts and disabled the Hotplug functionality
altogether. But the Root Ports does support reporting Hotplug events like
DL_Up/Down events.

So to fix the command completion timeout issues, just set the No Command
Completed Support (NCCS) bit and enable Hotplug in Slot Capability field
back.

Fixes: a54db86ddc153 ("PCI: qcom: Do not advertise hotplug capability for IPs v2.7.0 and v1.9.0")
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: renamed function, commit log and added comment]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Tested-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> # Hamoa CRD, tunneled link
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://patch.msgid.link/20260314-hotplug-v1-1-96ac87d93867@oss.qualcomm.com