thresholds: Add PerformanceLoss threshold

Create an xyz.openbmc_project.Sensor.Threshold.PerformanceLoss D-Bus
interface.  This could be placed on a sensor to:

a) Signal some other software to do something to the server that results
in performance loss, such as memory or CPU throttling, to bring down the
sensor value.

b) Trigger an event to the user so they know to expect a performance
loss, and which sensor caused it.

An immediate use of this will be on OpenPower systems to throttle the
CPU/memory and trigger event logs due to a high (virtual) ambient
temperature.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Id93843abdb45f00ee359f902d539b9df6bf5359a
diff --git a/gen/xyz/openbmc_project/Sensor/Threshold/meson.build b/gen/xyz/openbmc_project/Sensor/Threshold/meson.build
index ebc1c2e..e04269e 100644
--- a/gen/xyz/openbmc_project/Sensor/Threshold/meson.build
+++ b/gen/xyz/openbmc_project/Sensor/Threshold/meson.build
@@ -42,6 +42,21 @@
     build_by_default: true,
 )
 
+subdir('PerformanceLoss')
+generated_others += custom_target(
+    'xyz/openbmc_project/Sensor/Threshold/PerformanceLoss__markdown'.underscorify(),
+    input: [ meson.source_root() / 'xyz/openbmc_project/Sensor/Threshold/PerformanceLoss.interface.yaml',  ],
+    output: [ 'PerformanceLoss.md' ],
+    command: [
+        sdbuspp_gen_meson_prog, '--command', 'markdown',
+        '--output', meson.current_build_dir(),
+        '--tool', sdbusplusplus_prog,
+        '--directory', meson.source_root(),
+        'xyz/openbmc_project/Sensor/Threshold/PerformanceLoss',
+    ],
+    build_by_default: true,
+)
+
 subdir('SoftShutdown')
 generated_others += custom_target(
     'xyz/openbmc_project/Sensor/Threshold/SoftShutdown__markdown'.underscorify(),