Fully reset the chip like on a full up/down, but without the PHY
statemachine restart.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Backport of r48228
git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@48246 3c298f89-4303-0410-b956-a3cf2f4a3e73