uacce: fix isolate sysfs check condition

uacce: fix isolate sysfs check condition

uacce supports the device isolation feature. If the driver
implements the isolate_err_threshold_read and
isolate_err_threshold_write callback functions, uacce will create
sysfs files now. Users can read and configure the isolation policy
through sysfs. Currently, sysfs files are created as long as either
isolate_err_threshold_read or isolate_err_threshold_write callback
functions are present.

However, accessing a non-existent callback function may cause the
system to crash. Therefore, intercept the creation of sysfs if
neither read nor write exists; create sysfs if either is supported,
but intercept unsupported operations at the call site.

Fixes: e3e289fbc0b5 ("uacce: supports device isolation feature")
Cc: stable@vger.kernel.org
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://patch.msgid.link/20251202061256.4158641-3-huangchenghai2@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>