ARM: palmtreo: fix #ifdefs for leds-gpio device

The #ifdefs around the leds-gpio device platform data are erroneous.  Currently
the device is not instantiated on the centro unless CONFIG_MACH_TREO680 is
defined.  This patch eliminates the #ifdefs, and uses the machine_is_* macros to
initialize the data based on which machine the code is running on and the
build-time configuration.  Unused data is optimized out by the build tools if
build configuration does not enable support for both machines.

Tested on my palm treo 680, and compile-tested for all three combinations of
treo680/centro build configurations.

Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Acked-by: Tomas Cech <sleep_walker@suse.cz>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>