serial: add support for a no-name 4 ports multiserial card

It is a no-name PCI card.  I found no reference to a producer so I used
"UNKNOWN_0x1584" as the name.

Full lspci:
01:07.0 0780: 10b5:9050 (rev 01)
        Subsystem: 10b5:1584
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- \
                ParErr- Stepping- SERR+ FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- \
                DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Interrupt: pin A routed to IRQ 10
        Region 1: I/O ports at ec00 [size=128]
        Region 2: I/O ports at e480 [size=32]
        Region 3: I/O ports at e400 [size=8]
        Capabilities: [40] Power Management version 1
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA \
                        PME(D0+,D1-,D2-,D3hot+,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [48] #06 [0080]
        Capabilities: [4c] Vital Product Data

After:
0000:01:07.0: ttyS4 at I/O 0xe480 (irq = 10) is a 16550A
0000:01:07.0: ttyS5 at I/O 0xe488 (irq = 10) is a 16550A
0000:01:07.0: ttyS6 at I/O 0xe490 (irq = 10) is a 16550A
0000:01:07.0: ttyS7 at I/O 0xe498 (irq = 10) is a 16550A

Signed-off-by: Catalin(ux) M BOIE <catab@embedromix.ro>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>