dm: pcie_fsl: Fix the Class Code fixup function

The Class Code fixup method was changed from PCIe block
revision 3.0, the current fixup is only valid for the
revision 3.0 and the later ones.

So add the Class Code fixup for the block revision < 3.0.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/drivers/pci/pcie_fsl.c b/drivers/pci/pcie_fsl.c
index 1879d81..1be5063 100644
--- a/drivers/pci/pcie_fsl.c
+++ b/drivers/pci/pcie_fsl.c
@@ -503,14 +503,23 @@
 static int fsl_pcie_fixup_classcode(struct fsl_pcie *pcie)
 {
 	ccsr_fsl_pci_t *regs = pcie->regs;
+	u32 classcode_reg;
 	u32 val;
 
-	setbits_be32(&regs->dbi_ro_wr_en, 0x01);
-	fsl_pcie_hose_read_config_dword(pcie, PCI_CLASS_REVISION, &val);
+	if (pcie->block_rev >= PEX_IP_BLK_REV_3_0) {
+		classcode_reg = PCI_CLASS_REVISION;
+		setbits_be32(&regs->dbi_ro_wr_en, 0x01);
+	} else {
+		classcode_reg = CSR_CLASSCODE;
+	}
+
+	fsl_pcie_hose_read_config_dword(pcie, classcode_reg, &val);
 	val &= 0xff;
 	val |= PCI_CLASS_BRIDGE_PCI << 16;
-	fsl_pcie_hose_write_config_dword(pcie, PCI_CLASS_REVISION, val);
-	clrbits_be32(&regs->dbi_ro_wr_en, 0x01);
+	fsl_pcie_hose_write_config_dword(pcie, classcode_reg, val);
+
+	if (pcie->block_rev >= PEX_IP_BLK_REV_3_0)
+		clrbits_be32(&regs->dbi_ro_wr_en, 0x01);
 
 	return 0;
 }