PCI: qcom: Use default config space read function

Move the device class fudge to a proper fixup function, and remove
qcom_pcie_rd_own_conf() which has become useless.

dw_pcie_setup_rc() already did the right thing, but it's broken
on older qcom chips, such as 8064.

Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>