net: pcs: xpcs: propagate xpcs_read error to xpcs_get_state_c37_sgmii

While phylink_pcs_ops :: pcs_get_state does return void, xpcs_get_state()
does check for a non-zero return code from xpcs_get_state_c37_sgmii()
and prints that as a message to the kernel log.

However, a non-zero return code from xpcs_read() is translated into
"return false" (i.e. zero as int) and the I/O error is therefore not
printed. Fix that.

Fixes: b97b5331 ("net: pcs: add C37 SGMII AN support for intel mGbE controller")
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220720112057.3504398-1-vladimir.oltean@nxp.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/pcs/pcs-xpcs.c

@@ -896,7 +896,7 @@ static int xpcs_get_state_c37_sgmii(struct dw_xpcs *xpcs,
 	 */
 	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_INTR_STS);
 	if (ret < 0)
-		return false;
+		return ret;
 
 	if (ret & DW_VR_MII_C37_ANSGM_SP_LNKSTS) {
 		int speed_value;