livepatch: Use kallsyms_on_each_match_symbol() to improve performance

Based on the test results of kallsyms_on_each_match_symbol() and
kallsyms_on_each_symbol(), the average performance can be improved by
more than 1500 times.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>