sh: Show all clocks and their state in /proc/clocks

Show all clocks in /proc/clocks, and also show if they are enabled or
disabled. This is useful to show MSTPCR bits on SuperH Mobile processors.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>