uacce: use filep->f_mapping to replace inode->i_mapping

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I79JRM


CVE: NA

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The inode can be different in a container, for example, a docker and host
both open the same uacce parent device, which uses the same uacce struct
but different inode, so uacce->inode is not enough.

What's worse, when docker stopped, the inode will be destroyed as well,
causing use-after-free in uacce_remove.

So use q->filep->f_mapping to replace uacce->inode->i_mapping.

Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: JiangShui Yang <yangjiangshui@h-partners.com>