net: dsa: mv88e6xxx: prefix Port IEEE Priority mapping macros

For implicit namespacing and clarity, prefix the common Port IEEE
Priority Remapping registers macros with MV88E6095_PORT_IEEE_PRIO.

The 88E6390 family turned the 0x18 register into a single indirect
table, document that at the same time.

Document the register and prefer ordered hex masks values for all
Marvell 16-bit registers.

Also fix the following checkpatch checks with a temporary variable:

    CHECK: Alignment should match open parenthesis
    #65: FILE: drivers/net/dsa/mv88e6xxx/port.c:932:
    +		err = mv88e6xxx_port_ieeepmt_write(chip, port,
    +			   MV88E6390_PORT_IEEE_PRIO_MAP_TABLE_INGRESS_PCP,

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>