The HP mv2120 has several LEDs that are controlled through gpio.
Export the health LED, the red SATA LEDs as well as two gpios
that control the brightness of _all_ LEDs to userland.  The
Ethernet and power LEDs can't be controlled through gpio and the
blue SATA LEDs are handled via the SATA driver.
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>