net: stmmac: Fix mixed enum type warning

The commit 5a558611 ("net: stmmac: support FPE link partner
hand-shaking procedure") introduced the following coverity warning:

  "Parse warning (PW.MIXED_ENUM_TYPE)"
  "1. mixed_enum_type: enumerated type mixed with another type"

This is due to both "lo_state" and "lp_sate" which their datatype are
enum stmmac_fpe_state type, and being assigned with "FPE_EVENT_UNKNOWN"
which is a macro-defined of 0. Fixed this by assigned both these
variables with the correct enum value.

Fixes: 5a558611 ("net: stmmac: support FPE link partner hand-shaking procedure")
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -1021,8 +1021,8 @@ static void stmmac_fpe_link_state_handle(struct stmmac_priv *priv, bool is_up)
 	if (is_up && *hs_enable) {
 		stmmac_fpe_send_mpacket(priv, priv->ioaddr, MPACKET_VERIFY);
 	} else {
-		*lo_state = FPE_EVENT_UNKNOWN;
-		*lp_state = FPE_EVENT_UNKNOWN;
+		*lo_state = FPE_STATE_OFF;
+		*lp_state = FPE_STATE_OFF;
 	}
 }