Fix spelling mistakes using codespell

This commit corrects various spelling mistakes throughout the
repository. The corrections were made automatically using `codespell`[1]
tool.

[1]: https://github.com/codespell-project/codespell

Change-Id: Ia6b70713d3e9b77d6fd2d9400489ef7f02360364
Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
diff --git a/openpower-build-setup.sh b/openpower-build-setup.sh
index 1947ee7..efb3ebc 100755
--- a/openpower-build-setup.sh
+++ b/openpower-build-setup.sh
@@ -154,7 +154,7 @@
 set -x
 
 # This ensures that the alias set in op-build-env is
-# avalaible in this script
+# available in this script
 shopt -s expand_aliases
 
 cd "${WORKSPACE}"/op-build