dmaengine/ste_dma40: fix Oops due to double free of client descriptor

The client list may exist in two lists at the same time. This makes free
fail since the same desc is freed multiple times. Remove desc from
client list when adding it to the pending queue. Move free of client owned
descriptors from free_dma() to terminate_all().

Unable to handle kernel paging request at virtual address 00100104
pgd = dea8c000
[00100104] *pgd=1ea62831, *pte=00000000, *ppte=00000000
Internal error: Oops: 817 [#1] PREEMPT SMP
Modules linked in:
CPU: 0    Not tainted  (3.1.0-rc3+ #58)
PC is at d40_free_chan_resources+0x64/0x330

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>