dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc()

stable inclusion
from stable-v6.6.2
commit ca2294c1275ab57bd27d0a279ea0c8ed9fc0a029
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8IW7G

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ca2294c1275ab57bd27d0a279ea0c8ed9fc0a029



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[ Upstream commit 83c761f568733277ce1f7eb9dc9e890649c29a8c ]

If pxad_alloc_desc() fails on the first dma_pool_alloc() call, then
sw_desc->nb_desc is zero.
In such a case pxad_free_desc() is called and it will BUG_ON().

Remove this erroneous BUG_ON().

It is also useless, because if "sw_desc->nb_desc == 0", then, on the first
iteration of the for loop, i is -1 and the loop will not be executed.
(both i and sw_desc->nb_desc are 'int')

Fixes: a57e16cf ("dmaengine: pxa: add pxa dmaengine driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/c8fc5563c9593c914fde41f0f7d1489a21b45a9a.1696676782.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>