etmem: Fixed an issue where the module reference counting is incorrect

euleros inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I839LV


CVE: NA

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When the /proc/pid/idle_page and /proc/pid/swap_page are
opened, the try_module_get command is used to add reference
counting to prevent the module from being released.

However, if the file fails to be opened, the reference
count must be correctly released in the abnormal process.

Signed-off-by: liubo <liubo254@huawei.com>
(cherry picked from commit 02ca7219)