packagegroup-ni-extra: add gcore/gdb
packagegroup-ni-extra: add gcore/gdb

Requested via the feed request list (gcore which is part of gdb).
We currently add cgdb but it does not pull gdb in the feeds unless
we explicitely include it. (btw cgdb also rdepends on gdb so it's
useless without gdb. No one used it until now? )

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

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