net: phy: aquantia: check for NVMEM deferral

Currently, if NVMEM provider is probed later than Aquantia, loading the
firmware will fail with -EINVAL.

To fix this, simply check for -EPROBE_DEFER when NVMEM is attempted and
return it.

Fixes: e93984ebc1c8 ("net: phy: aquantia: add firmware load support")
Signed-off-by: Robert Marko <[e-mail]>
Reviewed-by: Russell King (Oracle) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/phy/aquantia/aquantia_firmware.c

···
 		 * assume that, and load a new image.
 		 */
 		ret = aqr_firmware_load_nvmem(phydev);
-		if (!ret)
+		if (ret == -EPROBE_DEFER || !ret)
 			return ret;
 
 		ret = aqr_firmware_load_fs(phydev);