Spelling fixes

Spelling errors found using github.com/lucasdemarchi/codespell
A tool to fix common misspellings.
This tool is licensed under GNU General Public License, version 2.

Change-Id: I1de3fdd00d0c132987b1eeb78b2945f30d3ab538
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/README b/README
index 968e06d..ff1c429 100644
--- a/README
+++ b/README
@@ -15,7 +15,7 @@
 * `notimpl` - These are read-only and write-only interface implementations that
 can be dropped into a pluggable sensor to make it complete.
 * `pid` - This contains all the PID associated code, including the zone
-defintion, controller definition, and the PID computational code.
+definition, controller definition, and the PID computational code.
 * `scripts` - This contains the scripts that convert YAML into C++.
 * `sensors` - This contains a couple of sensor types including the pluggable
 sensor's definition.  It also holds the sensor manager.