nilrt.conf: remove opencv-samples PREFFERED_PROVIDER
nilrt.conf: remove opencv-samples PREFFERED_PROVIDER

Starting with opencv 3.0 opencv-samples was merged in the main opencv
recipe so there's no need to specify a provider for it.

Signed-off-by: Ioan-Adrian Ratiu <7ec73abcfe099fc5574c01312b62768070c80980@ni.com>

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt