kernel/nata: Extract reset functions in chipset drivers.

kernel/nata: Extract reset functions in chipset drivers.

Explicitly do not import any port multipliers support for now.
Use only higher half of device signature, some devices return
incorrect values in lower part and causes issues in detection.
All of this is a bit messy in ata-ahci.c.

While there, include several later bugfixes.

Taken-from: FreeBSD