net: stmmac: move timestamping/ptp init to stmmac_hw_setup() caller

Move the call to stmmac_init_timestamping() or stmmac_setup_ptp() out
of stmmac_hw_setup() to its caller after stmmac_hw_setup() has
successfully completed. This slightly changes the ordering during
setup, but should be safe to do.

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