net: fsl/fman: rename IF_MODE_XGMII to IF_MODE_10G

[ Upstream commit 457bfc0a4bf531487ecc3cf82ec728a5e114fb1e ]

As the only 10G PHY interface type defined at the moment the code
was developed was XGMII, although the PHY interface mode used was
not XGMII, XGMII was used in the code to denote 10G. This patch
renames the 10G interface mode to remove the ambiguity.

Signed-off-by: Madalin Bucur <madalin.bucur@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>