Fix usage of zed_log_msg() and zfs_panic_recover()

Coverity complained about the format specifiers not matching variables.
In one case, the variable is a constant, so we fix it. In another, we
were missing an argument (about which coverity also complained).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13888