packagegroup-ni-extra: build chef only for x64
packagegroup-ni-extra: build chef only for x64

Chef's "json" dependency's build is not cross-compilation friendly, it
always assumes and builds x86-64 architecture binaries. Because json
fails to build chef also fails for arm, so build it only for x64.

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

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