Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 80e5358..0b22d51 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -81,7 +81,7 @@
 #include <linux/spinlock_types.h>
 
 /*
- * Pull the arch_spin*() functions/declarations (UP-nondebug doesnt need them):
+ * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
  */
 #ifdef CONFIG_SMP
 # include <asm/spinlock.h>