The "MT7621 Giga Switch Programming Guide v0.3", "MT7531 Reference Manual
for Development Board v1.0", and "MT7988A Wi-Fi 7 Generation Router
Platform: Datasheet (Open Version) v0.1" documents show that these bits are
enabled at reset:

PMCR_IFG_XMIT(1) (not part of PMCR_LINK_SETTINGS_MASK)
PMCR_MAC_MODE (not part of PMCR_LINK_SETTINGS_MASK)
PMCR_TX_EN
PMCR_RX_EN
PMCR_BACKOFF_EN (not part of PMCR_LINK_SETTINGS_MASK)
PMCR_BACKPR_EN (not part of PMCR_LINK_SETTINGS_MASK)
PMCR_TX_FC_EN
PMCR_RX_FC_EN

These bits also don't exist on the MT7530_PMCR_P(6) register of the switch
on the MT7988 SoC:

PMCR_IFG_XMIT()
PMCR_MAC_MODE
PMCR_BACKOFF_EN
PMCR_BACKPR_EN

Remove the setting of the bits not part of PMCR_LINK_SETTINGS_MASK on
phylink_mac_config as they're already set.

The bit for setting the port on force mode is already done on
mt7530_setup() and mt7531_setup_common(). So get rid of
PMCR_FORCE_MODE_ID() which helped determine which bit to use for the switch
model.
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>