rename away from RPM

The SetPoint output from a thermal PID is likely RPM, and that value is
then fed into a fan controller PID as the set-point (unit: RPM).  This
does not have to be RPM, however.  Continue renaming variables and
methods to remove the explicit unit-naming.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I570dee0c688338f9a458cac7123314717bee2b42
diff --git a/pid/fancontroller.cpp b/pid/fancontroller.cpp
index 1f23e0b..dd26d16 100644
--- a/pid/fancontroller.cpp
+++ b/pid/fancontroller.cpp
@@ -88,7 +88,7 @@
 
 double FanController::setptProc(void)
 {
-    double maxRPM = _owner->getMaxRPMRequest();
+    double maxRPM = _owner->getMaxSetPointRequest();
 
     // store for reference, and check if more or less.
     double prev = getSetpoint();