Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/arch/mips/mm/cex-sb1.S b/arch/mips/mm/cex-sb1.S
index 2d08268..89c412b 100644
--- a/arch/mips/mm/cex-sb1.S
+++ b/arch/mips/mm/cex-sb1.S
@@ -79,7 +79,7 @@
 recovered_dcache:
 	/*
 	 * Unlock CacheErr-D (which in turn unlocks CacheErr-DPA).
-	 * Ought to log the occurence of this recovered dcache error.
+	 * Ought to log the occurrence of this recovered dcache error.
 	 */
 	b	recovered
 	 mtc0	$0,C0_CERR_D