nilrt.conf: Replace DISTRO_FEATURES_append with DISTRO_FEATURES
nilrt.conf: Replace DISTRO_FEATURES_append with DISTRO_FEATURES

The default list includes unwanted features: "alsa argp bluetooth ext2
irda largefile pcmcia usbgadget usbhost wifi xattr nfs zeroconf pci 3g
nfc x11 ipv4 ipv6 pulseaudio sysvinit pam" and results in extra packages
beeing added to the image (like X11 libraries if dbus is present in the
image).

Natinst-P4-Changelist-ID: 8361276
Natinst-ReviewBoard-ID: 48425

Signed-off-by: Richard Tollerton <67c688e7f7482ba5c4ebe3d70bc77594748182a6@ni.com>

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