scsi: aha152x: drop host reset

The driver has both a bus and a host reset, where the host reset does a
bus reset followed by an attempt to reset the chip registers to a
default state.  However, as the bus reset always returned SUCCESS the
host reset was never called, so the functionality of the register reset
function was never validated.  Additionally, tha AIC-6260 chip has a
hard reset line, which actually should be preferred for a host
reset. But I haven't found a way how this can be triggered via software,
so take the safe approach and drop the host reset.

[mkp: typo]

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>