salt.bbappend: pont SRC_URI to github
salt.bbappend: pont SRC_URI to github

SL team decided to do their development on NI's github repo.

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

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