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/kernel/process.c b/arch/mips/kernel/process.c
index ae167df..d2112d3 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -410,7 +410,7 @@
 	if (!kallsyms_lookup_size_offset(pc, &size, &ofs))
 		return 0;
 	/*
-	 * Return ra if an exception occured at the first instruction
+	 * Return ra if an exception occurred at the first instruction
 	 */
 	if (unlikely(ofs == 0)) {
 		pc = *ra;