rt2x00: rt2x00pci_regbusy_read() - only print register access failure once

BugLink: http://bugs.launchpad.net/bugs/1128840

It appears that when this register read fails it never recovers, so
I think there is no need to repeat the same error message ad infinitum.

Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Gertjan van Wingerde <gwingerde@gmail.com>
Cc: Helmut Schaa <helmut.schaa@googlemail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: linux-wireless@vger.kernel.org
Cc: users@rt2x00.serialmonkey.com
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00pci.c

@@ -52,8 +52,8 @@ int rt2x00pci_regbusy_read(struct rt2x00_dev *rt2x00dev,
 		udelay(REGISTER_BUSY_DELAY);
 	}
 
-	ERROR(rt2x00dev, "Indirect register access failed: "
-	      "offset=0x%.08x, value=0x%.08x\n", offset, *reg);
+	printk_once(KERN_ERR "%s() Indirect register access failed: "
+	      "offset=0x%.08x, value=0x%.08x\n", __func__, offset, *reg);
 	*reg = ~0;
 
 	return 0;