PCI: rockchip-dwc: Reset core at driver probe

PCI: rockchip-dwc: Reset core at driver probe

The PCIe controller is in an unknown state at driver probe. This can
lead to undesireable effects when the driver attempts to configure the
controller.

Prevent issues in the future by resetting the core during probe.

Link: https://lore.kernel.org/r/20220429123832.2376381-3-pgwipeout@gmail.com
Tested-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>