random: remove some dead code of poolinfo

Since it is not being used, so delete it.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Link: https://lore.kernel.org/r/20190607182517.28266-5-tiny.windzz@gmail.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>