Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index 1e74ad9..3326615 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -129,7 +129,7 @@
 		return ret;
 
 	/*
-	 * Here we could argubly set the cache state to STATE_CLEAN.
+	 * Here we could arguably set the cache state to STATE_CLEAN.
 	 * However this could lead to inconsistency since we will not
 	 * be notified if this content is altered on the flash by other
 	 * means.  Let's declare it empty and leave buffering tasks to