Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/staging/speakup/keyhelp.c b/drivers/staging/speakup/keyhelp.c
index 23cf7f4..170f388 100644
--- a/drivers/staging/speakup/keyhelp.c
+++ b/drivers/staging/speakup/keyhelp.c
@@ -69,7 +69,7 @@
 	memset(key_offsets, 0, sizeof(key_offsets));
 	kp = state_tbl + nstates + 1;
 	while (*kp++) {
-		/* count occurrances of each function */
+		/* count occurrences of each function */
 		for (i = 0; i < nstates; i++, kp++) {
 			if (!*kp)
 				continue;