util-linux: add findfs option

Add the findfs utility option for util-linux package.

Signed-off-by: James Knight <james.knight@rockwellcollins.com>
Cc: Zheng Yi <yzheng@techyauld.com>
[Thomas: respect alphabetic ordering.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>