Update psu poll rate for phosphor-power-supply.

Use a hard-coded poll rate rather than the configuration value from
psu_config.json

Tested: Ran existing unit tests for phosphor-power with the build using
	meson -Doe-sdk=enabled -Dtests=enabled x86build
Tested: Using a psu_config.json file that did not contain a poll rate,
	demonstrating that pollInterval is no longer needed.
Tested: By adding temporary logging messages to verify successful
	 startup without existence of pollInterval field.

Signed-off-by: Jay Meyer <jaymeyer@us.ibm.com>
Change-Id: I969017c10474860f8b0a5f578a44a704c2f6a2e5
diff --git a/phosphor-power-supply/psu_manager.cpp b/phosphor-power-supply/psu_manager.cpp
index f31ba73..83fddd4 100644
--- a/phosphor-power-supply/psu_manager.cpp
+++ b/phosphor-power-supply/psu_manager.cpp
@@ -20,7 +20,7 @@
     getJSONProperties(configfile, bus, properties, psus);
 
     using namespace sdeventplus;
-    auto interval = std::chrono::milliseconds(properties.pollInterval);
+    auto interval = std::chrono::milliseconds(1000);
     timer = std::make_unique<utility::Timer<ClockId::Monotonic>>(
         e, std::bind(&PSUManager::analyze, this), interval);
 
@@ -61,13 +61,6 @@
 
     auto sysProps = configFileJSON["SystemProperties"];
 
-    if (!sysProps.contains("pollInterval"))
-    {
-        throw std::runtime_error("Missing required pollInterval property");
-    }
-
-    p.pollInterval = sysProps["pollInterval"];
-
     if (sysProps.contains("MinPowerSupplies"))
     {
         p.minPowerSupplies = sysProps["MinPowerSupplies"];