Spelling fixes

Spelling errors found using github.com/lucasdemarchi/codespell
A tool to fix common misspellings.
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Change-Id: Ia3256c0771a94cc44154a7f81af2dcfaf851ffa7
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/sysfs.hpp b/sysfs.hpp
index 2a22952..a203a8c 100644
--- a/sysfs.hpp
+++ b/sysfs.hpp
@@ -91,7 +91,7 @@
 
         /** @brief Perform formatted hwmon sysfs read.
          *
-         *  Propogates any exceptions other than ENOENT.
+         *  Propagates any exceptions other than ENOENT.
          *  ENOENT will result in a call to exit(0) in case
          *  the underlying hwmon driver is unbound and
          *  the program is inadvertently left running.
@@ -116,7 +116,7 @@
 
         /** @brief Perform formatted hwmon sysfs write.
          *
-         *  Propogates any exceptions other than ENOENT.
+         *  Propagates any exceptions other than ENOENT.
          *  ENOENT will result in a call to exit(0) in case
          *  the underlying hwmon driver is unbound and
          *  the program is inadvertently left running.