[ARM] pxa/spitz: use leds-gpio for led driving and drop leds-spitz

Now as the scoop pins are covered by the generic gpio API,
we can use leds-gpio driver instead of special leds-spitz

Drop leds-spitz.c and the declarations of now un-referenced
spitzscoop_device, spitzscoop2_device.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>