ARM: dts: imx7: Use audio_mclk_post_div instead audio_mclk_root_clk

stable inclusion
from stable-v5.10.110
commit 14df2556a190583125a001dd9cfa57c8a5c10b8b
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=14df2556a190583125a001dd9cfa57c8a5c10b8b



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[ Upstream commit 4cb7df64 ]

The audio_mclk_root_clk was added as a gate with the CCGR121 (0x4790),
but according to the reference manual, there is no such gate. Moreover,
the consumer driver of the mentioned clock might gate it and leave
the ECSPI2 (the true owner of that gate) hanging. So lets use the
audio_mclk_post_div, which is the parent.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>