[PATCH] idmouse cleanup and overflow fix

switched to simple_read_from_buffer(), killed broken use of min().
Incidentally, that use of min() had been fixed once, only to be
reintroduced in commit 4244f724:

    [PATCH] USB: upgrade of the idmouse driver

[snip]
-       if (count > IMGSIZE - *ppos)
-               count = IMGSIZE - *ppos;
+       count = min ((loff_t)count, IMGSIZE - (*ppos));

Note the lovely use of cast to shut the warning about misuse of min()
up...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>