smsc95xx: Fetch whole burst with 1 URB, avoid framing errors

smsc95xx_recv() does not reassemble bursts spread over multiple URBs.
If there is a lot of broadcast traffic, the fifo will fill up to the
burst cap limit. Lowering the burst cap to the URB size ensures no packet
spans multiple urbs.
Caveat, lower limit for working burst cap is 5/33 HS/FS packets.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

drivers/usb/eth/smsc95xx.c

@@ -120,8 +120,9 @@
 /* Some extra defines */
 #define HS_USB_PKT_SIZE			512
 #define FS_USB_PKT_SIZE			64
-#define DEFAULT_HS_BURST_CAP_SIZE	(16 * 1024 + 5 * HS_USB_PKT_SIZE)
-#define DEFAULT_FS_BURST_CAP_SIZE	(6 * 1024 + 33 * FS_USB_PKT_SIZE)
+/* 5/33 is lower limit for BURST_CAP to work */
+#define DEFAULT_HS_BURST_CAP_SIZE	(5 * HS_USB_PKT_SIZE)
+#define DEFAULT_FS_BURST_CAP_SIZE	(33 * FS_USB_PKT_SIZE)
 #define DEFAULT_BULK_IN_DELAY		0x00002000
 #define MAX_SINGLE_PACKET_SIZE		2048
 #define EEPROM_MAC_OFFSET		0x01
@@ -135,7 +136,7 @@
 #define USB_BULK_SEND_TIMEOUT 5000
 #define USB_BULK_RECV_TIMEOUT 5000
 
-#define RX_URB_SIZE 2048
+#define RX_URB_SIZE DEFAULT_HS_BURST_CAP_SIZE
 #define PHY_CONNECT_TIMEOUT 5000
 
 #define TURBO_MODE