leds-net5501: taints kernel, add license

Add MODULE_LICENSE() that matches file comments so that kernel
is not tainted.

	leds_net5501: module license 'unspecified' taints kernel.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>