Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/Documentation/irqflags-tracing.txt b/Documentation/irqflags-tracing.txt
index 6a44487..67aa71e 100644
--- a/Documentation/irqflags-tracing.txt
+++ b/Documentation/irqflags-tracing.txt
@@ -53,5 +53,5 @@
 turn itself off. I.e. the lock validator will still be reliable. There
 should be no crashes due to irq-tracing bugs. (except if the assembly
 changes break other code by modifying conditions or registers that
-shouldnt be)
+shouldn't be)