rename RPMSetPoint to SetPoint

The PIDs were originally focused on collecting RPM set points from
thermal PIDs and then having fan PIDs use the highest value collected,
it doesn't need to be strictly an RPM set point.

It does however need to be one type of value.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I1d589cf4b2688d7e86030c10496d737dc5bbdadf
diff --git a/pid/pidloop.cpp b/pid/pidloop.cpp
index 9eed3a8..b86ea4b 100644
--- a/pid/pidloop.cpp
+++ b/pid/pidloop.cpp
@@ -31,8 +31,8 @@
 {
     // Get the latest margins.
     zone->updateSensors();
-    // Zero out the RPM set point goals.
-    zone->clearRPMSetPoints();
+    // Zero out the set point goals.
+    zone->clearSetPoints();
     zone->clearRPMCeilings();
     // Run the margin PIDs.
     zone->processThermals();