ahci: link FIS receive mode to memory allocation
ahci: link FIS receive mode to memory allocation

There is no need to set/clear PxCMD.FRE on every port start/stop.

Also remove some already useless and now also incomplete port
reinitialization at startup.

veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi