The input layer wants to send us an entropy event per input event and who are
we to argue?  Create add_input_randomness with an input-friendly interface and
kill the remaining two keyboard and mouse sources.

This eliminates lots of duplicate entropy events while covering all the input
bases nicely.  We now get two events per keystroke as we should, one down and
one up.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>