cxl/pci: Use pci core's DVSEC functionality

Reduce maintenance burden of DVSEC query implementation by using the
centralized PCI core implementation.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
[djbw: kill cxl_pci_dvsec()]
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/163379788528.692348.11581080806976608802.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Author: Ben Widawsky

drivers/cxl/pci.c

@@ -340,29 +340,6 @@ static void cxl_unmap_regblock(struct pci_dev *pdev,
 	map->base = NULL;
 }
 
-static int cxl_pci_dvsec(struct pci_dev *pdev, int dvsec)
-{
-	int pos;
-
-	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DVSEC);
-	if (!pos)
-		return 0;
-
-	while (pos) {
-		u16 vendor, id;
-
-		pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER1, &vendor);
-		pci_read_config_word(pdev, pos + PCI_DVSEC_HEADER2, &id);
-		if (vendor == PCI_DVSEC_VENDOR_ID_CXL && dvsec == id)
-			return pos;
-
-		pos = pci_find_next_ext_capability(pdev, pos,
-						   PCI_EXT_CAP_ID_DVSEC);
-	}
-
-	return 0;
-}
-
 static int cxl_probe_regs(struct pci_dev *pdev, struct cxl_register_map *map)
 {
 	struct cxl_component_reg_map *comp_map;
@@ -449,7 +426,8 @@ static int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
 	u32 regloc_size, regblocks;
 	int regloc, i;
 
-	regloc = cxl_pci_dvsec(pdev, PCI_DVSEC_ID_CXL_REGLOC_DVSEC_ID);
+	regloc = pci_find_dvsec_capability(pdev, PCI_DVSEC_VENDOR_ID_CXL,
+					   PCI_DVSEC_ID_CXL_REGLOC_DVSEC_ID);
 	if (!regloc)
 		return -ENXIO;