[PATCH] s2io: performance improvements

hi,
	This patch contains all the changes that were done to improve
	performance of s2io driver. one line  description of the changes
	are

	1. For Non NAPI case the rx interrupt handler is being called
	   unconditionally
	2. code optimization and adding prefetch skb->data
	3. Remove modulo operations in fast path
	4. Enable Group Reads and set backoff interval to 0x1000
	5. correct PIC_CNTL_SHARED_SPLITS  macro definition, and reduce
	   pause parameter
	6. Corrected logic of identifying rx buffer level in rx_buffer_level()
	7. fix DMA map and unmap done with different sizes in 1-buf mode
	8. Removed forcible disabling of ERO
	9. Send up the packets with transfer code = 0x5

Signed-off-by: Ananda Raju <ananda.raju@neterion.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>