Phonet: restore flow control credits when sending fails

This patch restores the below flow control patch submitted by Rémi
Denis-Courmont, which accidentaly got lost due to Pipe controller patch
on Phonet.

	commit 1a98214f
	Author: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
	Date:   Mon Aug 30 12:57:03 2010 +0000

	Phonet: restore flow control credits when sending fails

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Kumar Sanghvi <kumar.sanghvi@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>