Cleanup old headers and namespace declarations

Remove the header includes for the old phosphor::logging::log API
as well as unnecessary phosphor::logging namespace declarations.
Fully qualify phosphor::logging namespace where applicable and/or
needed.

Tested:
* Verified commit passed CI unit tests.
* Verified commit built using bitbake.

Change-Id: I2e490e1aa3fd3423f8c52694c2b97bc58b95525a
Signed-off-by: Anwaar Hadi <anwaar.hadi@ibm.com>
diff --git a/monitor/conditions.cpp b/monitor/conditions.cpp
index 91d6a54..84f8ec2 100644
--- a/monitor/conditions.cpp
+++ b/monitor/conditions.cpp
@@ -18,7 +18,6 @@
 {
 
 using json = nlohmann::json;
-using namespace phosphor::logging;
 
 Condition propertiesMatch(std::vector<PropertyState>&& propStates)
 {
diff --git a/monitor/fan.cpp b/monitor/fan.cpp
index ab8d46d..f2f562c 100644
--- a/monitor/fan.cpp
+++ b/monitor/fan.cpp
@@ -32,7 +32,6 @@
 namespace monitor
 {
 
-using namespace phosphor::logging;
 using namespace sdbusplus::bus::match;
 
 Fan::Fan(Mode mode, sdbusplus::bus_t& bus, const sdeventplus::Event& event,
diff --git a/monitor/json_parser.cpp b/monitor/json_parser.cpp
index f24fd61..57bfdbd 100644
--- a/monitor/json_parser.cpp
+++ b/monitor/json_parser.cpp
@@ -36,7 +36,6 @@
 {
 
 using json = nlohmann::json;
-using namespace phosphor::logging;
 
 namespace tClass
 {
diff --git a/monitor/system.cpp b/monitor/system.cpp
index ff074c3..9620c09 100644
--- a/monitor/system.cpp
+++ b/monitor/system.cpp
@@ -44,8 +44,6 @@
 using json = nlohmann::json;
 using Severity = sdbusplus::xyz::openbmc_project::Logging::server::Entry::Level;
 
-using namespace phosphor::logging;
-
 const std::string System::dumpFile = "/tmp/fan_monitor_dump.json";
 
 System::System(Mode mode, sdbusplus::bus_t& bus,
diff --git a/monitor/tach_sensor.cpp b/monitor/tach_sensor.cpp
index 5790bab..cce3139 100644
--- a/monitor/tach_sensor.cpp
+++ b/monitor/tach_sensor.cpp
@@ -343,7 +343,7 @@
             // Log an internal error for undefined timer mode
             lg2::error("Undefined timer mode: {TIMER_MODE}", "TIMER_MODE",
                        mode);
-            elog<InternalFailure>();
+            phosphor::logging::elog<InternalFailure>();
             return duration_cast<microseconds>(seconds(0));
     }
 }