DellEMC S6100: Determine pcie.yaml revision based on firmware (#7875)

Why I did it
To determine the revision of the pcie.yaml to be used based on BIOS version in DellEMC S6100 platform.

Depends on: Azure/sonic-platform-common#195

How I did it
Added two revisions of pcie.yaml pcie_1.yaml and pcie_2.yaml
Included a platform-specific Pcie class to provide the revision of the pcie.yaml to be used by pcieutil/pcied.
How to verify it
Execute pcieutil check (Azure/sonic-utilities#1672) command and verify the list of PCIe devices displayed.
Logs: UT_logs.txt

device/dell/x86_64-dell_s6100_c2538-r0/pcie_2.yaml

@@ -0,0 +1,50 @@
+- bus: '00'
+  dev: '01'
+  fn: '0'
+  id: 1f10
+  name: 'PCI bridge: Intel Corporation Atom processor C2000 PCIe Root Port 1'
+- bus: '00'
+  dev: '03'
+  fn: '0'
+  id: 1f12
+  name: 'PCI bridge: Intel Corporation Atom processor C2000 PCIe Root Port 3'
+- bus: '00'
+  dev: '04'
+  fn: '0'
+  id: 1f13
+  name: 'PCI bridge: Intel Corporation Atom processor C2000 PCIe Root Port 4'
+- bus: '00'
+  dev: 0f
+  fn: '0'
+  id: 1f16
+  name: 'IOMMU: Intel Corporation Atom processor C2000 RCEC'
+- bus: '00'
+  dev: '13'
+  fn: '0'
+  id: 1f15
+  name: 'System peripheral: Intel Corporation Atom processor C2000 SMBus 2.0'
+- bus: '00'
+  dev: '14'
+  fn: '0'
+  id: 1f41
+  name: 'Ethernet controller: Intel Corporation Ethernet Connection I354'
+- bus: '00'
+  dev: '14'
+  fn: '1'
+  id: 1f41
+  name: 'Ethernet controller: Intel Corporation Ethernet Connection I354'
+- bus: '00'
+  dev: '14'
+  fn: '2'
+  id: 1f41
+  name: 'Ethernet controller: Intel Corporation Ethernet Connection I354'
+- bus: '01'
+  dev: '00'
+  fn: '0'
+  id: b960
+  name: 'Ethernet controller: Broadcom Limited Broadcom BCM56960 Switch ASIC'
+- bus: '01'
+  dev: '00'
+  fn: '1'
+  id: b960
+  name: 'Ethernet controller: Broadcom Limited Broadcom BCM56960 Switch ASIC'

platform/broadcom/sonic-platform-modules-dell/s6100/sonic_platform/pcie.py

@@ -0,0 +1,29 @@
+########################################################################
+#
+# DELLEMC S6100
+#
+# Module contains a platform specific implementation of SONiC Platform
+# Base PCIe class
+#
+########################################################################
+
+try:
+    from sonic_platform.component import Component
+    from sonic_platform_base.sonic_pcie.pcie_common import PcieUtil
+except ImportError as e:
+    raise ImportError(str(e) + "- required module not found")
+
+
+class Pcie(PcieUtil):
+    """DellEMC Platform-specific PCIe class"""
+
+    def __init__(self, platform_path):
+        PcieUtil.__init__(self, platform_path)
+        bios = Component(component_index=0)
+        bios_ver = bios.get_firmware_version()
+
+        versions = bios_ver.split("-")
+        if (len(versions) == 2) and int(versions[1], 10) > 5:
+            self._conf_rev = "2"
+        else:
+            self._conf_rev = "1"