X86 vs PowerPC Serial port

On X86:
[    3.162453] Serial: 8250/16550 driver4 ports, IRQ sharing enabled
[    3.443900] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A


On PowerPC:
Registering platform device 'serial8250.0'. Parent at platform
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled
Registering platform device 'serial8250'. Parent at platform
ttyS0 at MMIO 0xe0004500 (irq = 9) is a 16550A
ttyS1 at MMIO 0xe0004600 (irq = 9) is a 16550A
ttyS0 at MMIO 0xe0004500 (irq = 9) is a 16550A
ttyS1 at MMIO 0xe0004600 (irq = 10) is a 16550A