opkg: ensure opkg uses private gpg.conf when applying keys.

Currently, the opkg-key utility calls gpg with --no-options,
which uses /dev/null as the configuration file. This means
any configurations in /etc/opkg/gpg/gpg.conf were being
ignored. This change applies a patch to remove the
--no-options flag.

Signed-off-by: Charlie Johnston <charlie.johnston@ni.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>