Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/sound/pci/rme96.c b/sound/pci/rme96.c
index d5f5b44..9ff247f 100644
--- a/sound/pci/rme96.c
+++ b/sound/pci/rme96.c
@@ -150,7 +150,7 @@
 #define RME96_RCR_BITPOS_F1 28
 #define RME96_RCR_BITPOS_F2 29
 
-/* Additonal register bits */
+/* Additional register bits */
 #define RME96_AR_WSEL       (1 << 0)
 #define RME96_AR_ANALOG     (1 << 1)
 #define RME96_AR_FREQPAD_0  (1 << 2)