net: stmmac: fix PTP error cleanup in __stmmac_open()

net: stmmac: fix PTP error cleanup in __stmmac_open()

The cleanup function for stmmac_setup_ptp() is stmmac_release_ptp()
which entirely undoes the effects of stmmac_setup_ptp() by
unregistering the PTP device and then stopping the PTP clock,
whereas stmmac_hw_teardown() will only stop the PTP clock while
leaving the PTP device registered.

This can lead to a kernel oops - if __stmmac_open() fails after
registering the PTP clock, the PTP device will remain registered,
and if the module is removed, subsequent PTP device accesses will
lead to a kernel oops.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>