Documentation: update /proc/uptime field description
Documentation: update /proc/uptime field description

/proc/uptime has two fields, update description to describe both
ala http://lkml.indiana.edu/hypermail/linux/kernel/1312.3/01454.html

Signed-off-by: Rob Landley <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@landley.net>
Signed-off-by: Jiri Kosina <ed58f755cc8caaf10c3e8c731a8b86fb8f13d6cb@suse.cz>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs