Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index f023ba6..1971bcf 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -367,7 +367,7 @@
 suspend methods were called, for example by complete reinitialization.
 This may be the hardest part, and the one most protected by NDA'd documents
 and chip errata.  It's simplest if the hardware state hasn't changed since
-the suspend was carried out, but that can't be guaranteed (in fact, it ususally
+the suspend was carried out, but that can't be guaranteed (in fact, it usually
 is not the case).
 
 Drivers must also be prepared to notice that the device has been removed