Correct typographical errors

Corrects typos in core code, documentation files, drivers, Arm
platforms and services.

None of the corrections affect code; changes are limited to comments
and other documentation.

Change-Id: I5c1027b06ef149864f315ccc0ea473e2a16bfd1d
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/psci-lib-integration-guide.rst b/docs/psci-lib-integration-guide.rst
index d86fc29..1be2240 100644
--- a/docs/psci-lib-integration-guide.rst
+++ b/docs/psci-lib-integration-guide.rst
@@ -240,7 +240,7 @@
 the EL3 Runtime Software may want to perform some bookkeeping during power
 management operations. This function is used to register the ``spd_pm_ops_t``
 (first argument) callbacks with the PSCI library which will be called
-ppropriately during power management. Calling this function is optional and
+appropriately during power management. Calling this function is optional and
 need to be called by the primary CPU during the cold boot sequence after
 ``psci_setup()`` has completed.