pcie_bifurcation: Fetch bifurcation at a PCIe slot with hardcoded values

This will read a json config and return the bifurcation based on that.
It will read the configure file in a persistent file to see if it is
valid machine config and return the bifurcation information
accordingly.

For example,
If it is valid config, it will return 8x8 for PE1,3,4,6.

Tested:
Unit tests passed.

Physical Tests.

PE0 -> no bifurcation
PE1 -> x8x8

```
$ ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x0f 0
 79 2b 00 0b 00

$ ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x0f 1
 79 2b 00 0b 02 08 08
```

Change-Id: I44aefbfb26372f8bc0069343c8a6d07d3cf6f42d
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/meson.build b/meson.build
index d561fdc..a2e8d1b 100644
--- a/meson.build
+++ b/meson.build
@@ -9,6 +9,14 @@
     'werror=true',
   ])
 
+root_inc = include_directories('.')
+
+conf_data = configuration_data()
+conf_data.set_quoted('STATIC_BIFURCATION_CONFIG', get_option('static-bifurcation'))
+conf_h = configure_file(
+  output: 'config.h',
+  configuration: conf_data)
+
 meson.get_compiler('cpp').has_header_symbol(
   'ipmid/api.h',
   'ipmid_get_sd_bus_connection')
@@ -19,13 +27,30 @@
   'nlohmann::json',
   dependencies: json_dep)
 
+fmt_dep = dependency('fmt', required: false)
+if not fmt_dep.found()
+  fmt_proj = import('cmake').subproject(
+    'fmt',
+    cmake_options: [
+      '-DCMAKE_POSITION_INDEPENDENT_CODE=ON',
+      '-DMASTER_PROJECT=OFF'
+    ],
+    required: false)
+  assert(fmt_proj.found(), 'fmtlib is required')
+  fmt_dep = fmt_proj.dependency('fmt')
+endif
+
+subdir('bifurcation')
+
 sys_pre = declare_dependency(
-  include_directories: include_directories('.'),
+  include_directories: root_inc,
   dependencies: [
     json_dep,
+    fmt_dep,
     dependency('phosphor-dbus-interfaces'),
     dependency('phosphor-logging'),
     dependency('sdbusplus'),
+    bifurcation_dep,
   ])
 
 sys_lib = static_library(
@@ -41,6 +66,7 @@
   'machine_name.cpp',
   'pcie_i2c.cpp',
   'google_accel_oob.cpp',
+  'pcie_bifurcation.cpp',
   'psu.cpp',
   'util.cpp',
   implicit_include_directories: false,