[issue1648] AHCI driver reports FIS structure fails

[Matthew Dillon]

:ahci0.1: PMPROBE First FIS failed
:ahci0.0.15: Poll timeout slot 1 CMD: 26016<PMA,FR,MPSS,FRE,POD,SUD> TFD: 0x=
:150
:SERR: c0000<DIAG.B,DIAG.W>
:ahci0.0: PMPROBE First FIS failed
:..
:
:ahci0.1: PMPROBE Second FIS failed
:ahci0.0: PMPROBE Second FIS failed

    If you don't have a port multiplier connected those messages can
    be ignored.  Does it detect the attached devices?  

						-Matt