drivers/perf: convert sysfs sprintf family to sysfs_emit

sprintf does not know the PAGE_SIZE maximum of the temporary buffer
used for sysfs content and it's possible to overrun the buffer length.

Use sysfs_emit() function to ensures that no overrun is done.

Signed-off-by: Qi Liu <liuqi115@huawei.com>
Link: https://lore.kernel.org/r/1616148273-16374-4-git-send-email-liuqi115@huawei.com


Signed-off-by: Will Deacon <will@kernel.org>