net: stmmac: Fix stmmac_get_rx_hwtstamp()
When using GMAC4 the valid timestamp is from CTX next desc but
we are passing the previous desc to get_rx_timestamp_status()
callback.
Fix this and while at it rework a little bit the function logic.
Signed-off-by: Jose Abreu <joabreu at synopsys.com>
Cc: David S. Miller <davem at davemloft.net>
Cc: Joao Pinto <jpinto at synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro at st.com>
Cc: Alexandre Torgue <alexandre.torgue at st.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
UnifiedSplitRaw