PCI: qcom: Use DWC helpers for modifying the read-only DBI registers

DWC core already exposes dw_pcie_dbi_ro_wr_{en/dis} helper APIs for
enabling and disabling the write access to read only DBI registers. So
let's use them instead of doing it manually.

Also, the existing code doesn't disable the write access when it's done.
This is also fixed now.

Link: https://lore.kernel.org/r/20230619150408.8468-3-manivannan.sadhasivam@linaro.org
Fixes: 5d76117 ("PCI: qcom: Add support for IPQ8074 PCIe controller")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Author: Mani-Sadhasivam

drivers/pci/controller/dwc/pcie-qcom.c

@@ -61,7 +61,6 @@
 /* DBI registers */
 #define AXI_MSTR_RESP_COMP_CTRL0		0x818
 #define AXI_MSTR_RESP_COMP_CTRL1		0x81c
-#define MISC_CONTROL_1_REG			0x8bc
 
 /* MHI registers */
 #define PARF_DEBUG_CNT_PM_LINKST_IN_L2		0xc04
@@ -132,9 +131,6 @@
 /* AXI_MSTR_RESP_COMP_CTRL1 register fields */
 #define CFG_BRIDGE_SB_INIT			BIT(0)
 
-/* MISC_CONTROL_1_REG register fields */
-#define DBI_RO_WR_EN				1
-
 /* PCI_EXP_SLTCAP register fields */
 #define PCIE_CAP_SLOT_POWER_LIMIT_VAL		FIELD_PREP(PCI_EXP_SLTCAP_SPLV, 250)
 #define PCIE_CAP_SLOT_POWER_LIMIT_SCALE		FIELD_PREP(PCI_EXP_SLTCAP_SPLS, 1)
@@ -826,7 +822,9 @@ static int qcom_pcie_post_init_2_3_3(struct qcom_pcie *pcie)
 	writel(0, pcie->parf + PARF_Q2A_FLUSH);
 
 	writel(PCI_COMMAND_MASTER, pci->dbi_base + PCI_COMMAND);
-	writel(DBI_RO_WR_EN, pci->dbi_base + MISC_CONTROL_1_REG);
+
+	dw_pcie_dbi_ro_wr_en(pci);
+
 	writel(PCIE_CAP_SLOT_VAL, pci->dbi_base + offset + PCI_EXP_SLTCAP);
 
 	val = readl(pci->dbi_base + offset + PCI_EXP_LNKCAP);