net: phy: nxp-c45-tja11xx: use local definion of features

Use a local definition for the PHY features. PHY_100BT1_FEATURES are
not defined using the 100BaseT1 bit, so keep this workaround in the driver.

Signed-off-by: "Radu Pirea (NXP OSS)" <radu-nicolae.pirea@oss.nxp.com>