remove historical workaround for 32bit /proc/stat

/proc/stat was converted to 64bit at kernel 2.6.5 (at 2004). 10 years later,
a workaround for 32bit /proc/stat become completely outdated. It's time to die.
This patch removes the workaround.

For the record, you can see the kernel commit that changed /proc/stat to 64bit
in the following URL.
http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/?id=0281d847f3a903ab9d0799c5103416d4893fcb34

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
workaround for /proc/stat go backward

Since dyn-tick feature was introduced (at kernel 2.6.21),
/proc/stat is unreliable and unstable. Stopped cpu can't provide
reliable stat. kernel try to provide a maximum guess. But it is
not 100% accurate.

Unfortunately, the fields are unsigned. So, stepping backward
can make overflow and some command (e.g. mpstat) show very big
number.

This patch provide a workaround.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Merge branch 'workaround-mpstat-overflow' of https://github.com/kosaki/sysstat

Added comments for ll_sp_value() function.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>