ARM: shmobile: koelsch: Enable CONFIG_PACKET in defconfig

CONFIG_PACKET is required for the ISC dhcpd daemon function.
This change brings the koelsch defconfig into line with
other shmobile defconfigs.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>