rt2800usb: add RXINFO_DESC_SIZE definition

Add RXINFO_DESC_SIZE definition and use it instead of abusing
RXD_DESC_SIZE one (TXD_DESC_SIZE and RXD_DESC_SIZE are specific
to PCI version of the chipset).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2800usb.h b/drivers/net/wireless/rt2x00/rt2800usb.h
index 7b1130a..9d7bb54 100644
--- a/drivers/net/wireless/rt2x00/rt2800usb.h
+++ b/drivers/net/wireless/rt2x00/rt2800usb.h
@@ -1747,7 +1747,8 @@
 #define TXD_DESC_SIZE			( 4 * sizeof(__le32) )
 #define TXINFO_DESC_SIZE		( 1 * sizeof(__le32) )
 #define TXWI_DESC_SIZE			( 4 * sizeof(__le32) )
-#define RXD_DESC_SIZE			( 1 * sizeof(__le32) )
+#define RXD_DESC_SIZE			( 4 * sizeof(__le32) )
+#define RXINFO_DESC_SIZE		( 1 * sizeof(__le32) )
 #define RXWI_DESC_SIZE			( 4 * sizeof(__le32) )
 
 /*