OMAP3: igep0032: Fix regression due commit f3b4bc45.

Commit referenced in subject breaks IGEP0032 build with the following
error:

  drivers/misc/status_led.c:30:7: error: 'RED_LED_GPIO' undeclared here (not in a function)
  scripts/Makefile.build:275: recipe for target 'drivers/misc/status_led.o' failed
  make[2]: *** [drivers/misc/status_led.o] Error 1
  scripts/Makefile.build:420: recipe for target 'drivers/misc' failed
  make[1]: *** [drivers/misc] Error 2
  Makefile:1093: recipe for target 'drivers' failed
  make: *** [drivers] Error 2

Fix this by skipping the status led on IGEP0032 machine as is not available
and throw an error for future machines if the status led is not configured
to avoid build breakage.

Reported-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>