PCI: qcom: Drop the assert_perst() callbacks

PCI: qcom: Drop the assert_perst() callbacks

Previously, the pcie-qcom driver probed first, deasserted PERST#, enabled
link training and scanned the bus. By the time the pwrctrl driver probe got
called, link training was already enabled by the controller driver.

Thus the pwrctrl drivers had to call the .assert_perst() callback, to
assert PERST#, power on the needed resources, and then call the
.assert_perst() callback to deassert PERST#.

Now since all pwrctrl drivers and this controller driver have been
converted to the new pwrctrl design where the pwrctrl drivers will first
power on the devices before this driver deasserts PERST# and scan the bus.
So there is no longer a need for .assert_perst() callback in this driver
and in DWC core driver. Hence, drop them.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260115-pci-pwrctrl-rework-v5-13-9d26da3ce903@oss.qualcomm.com