iwlegacy: always check if got h/w access before write

Before we write to the device register always check if
_il_grap_nic_access() was successful.

Change type return type _il_grap_nic_access() to bool, and
add likely()/unlikely() statements.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlegacy/common.c b/drivers/net/wireless/iwlegacy/common.c
index 3900967..6dbd11f 100644
--- a/drivers/net/wireless/iwlegacy/common.c
+++ b/drivers/net/wireless/iwlegacy/common.c
@@ -81,7 +81,7 @@
 }
 EXPORT_SYMBOL(il_clear_bit);
 
-int
+bool
 _il_grab_nic_access(struct il_priv *il)
 {
 	int ret;
@@ -116,10 +116,10 @@
 		WARN_ONCE(1, "Timeout waiting for ucode processor access "
 			     "(CSR_GP_CNTRL 0x%08x)\n", val);
 		_il_wr(il, CSR_RESET, CSR_RESET_REG_FLAG_FORCE_NMI);
-		return -EIO;
+		return false;
 	}
 
-	return 0;
+	return true;
 }
 EXPORT_SYMBOL_GPL(_il_grab_nic_access);
 
@@ -161,7 +161,7 @@
 	unsigned long reg_flags;
 
 	spin_lock_irqsave(&il->reg_lock, reg_flags);
-	if (!_il_grab_nic_access(il)) {
+	if (likely(_il_grab_nic_access(il))) {
 		_il_wr_prph(il, addr, val);
 		_il_release_nic_access(il);
 	}
@@ -194,7 +194,7 @@
 	unsigned long reg_flags;
 
 	spin_lock_irqsave(&il->reg_lock, reg_flags);
-	if (!_il_grab_nic_access(il)) {
+	if (likely(_il_grab_nic_access(il))) {
 		_il_wr(il, HBUS_TARG_MEM_WADDR, addr);
 		wmb();
 		_il_wr(il, HBUS_TARG_MEM_WDAT, val);