ASoC: skl-topology: Use kmemdup to replace kzalloc + memcpy

kmemdup has implemented the function that kzalloc() + memcpy() will
do. and we prefer to kmemdup rather than the open coded implementation.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>