PCI: dwc: Export more symbols to allow modular drivers

These symbols are used by the pci-dra7xx driver. Export them to allow
building pci-dra7xx as a module.

Link: https://lore.kernel.org/r/20210531085934.2662457-2-luca@lucaceresoli.net


Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>