scsi: sun_esp: don't use GFP_ATOMIC for command block allocation

esp_sbus_map_command_block is called straight from the probe routine
without any locks held, so we can safely use GFP_KERNEL here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>