Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/net/wireless/iwlegacy/iwl-core.c b/drivers/net/wireless/iwlegacy/iwl-core.c
index d418b64..1c3a8cb 100644
--- a/drivers/net/wireless/iwlegacy/iwl-core.c
+++ b/drivers/net/wireless/iwlegacy/iwl-core.c
@@ -1030,7 +1030,7 @@
 	/*
 	 * Enable HAP INTA (interrupt from management bus) to
 	 * wake device's PCI Express link L1a -> L0s
-	 * NOTE:  This is no-op for 3945 (non-existant bit)
+	 * NOTE:  This is no-op for 3945 (non-existent bit)
 	 */
 	iwl_legacy_set_bit(priv, CSR_HW_IF_CONFIG_REG,
 				    CSR_HW_IF_CONFIG_REG_BIT_HAP_WAKE_L1A);