iwlwifi: add iwl_set_bits_mask

In a few cases we need to set a value in
a certain mask inside a register, add the
function iwl_set_bits_mask() to make such
code easy.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-io.h b/drivers/net/wireless/iwlwifi/iwl-io.h
index abb3250..4a9a45f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-io.h
+++ b/drivers/net/wireless/iwlwifi/iwl-io.h
@@ -54,6 +54,8 @@
 void iwl_set_bit(struct iwl_trans *trans, u32 reg, u32 mask);
 void iwl_clear_bit(struct iwl_trans *trans, u32 reg, u32 mask);
 
+void iwl_set_bits_mask(struct iwl_trans *trans, u32 reg, u32 mask, u32 value);
+
 int iwl_poll_bit(struct iwl_trans *trans, u32 addr,
 		 u32 bits, u32 mask, int timeout);
 int iwl_poll_direct_bit(struct iwl_trans *trans, u32 addr, u32 mask,