ata: pata_atiixp: Avoid overwriting initialised field in 'atiixp_sht'

ata: pata_atiixp: Avoid overwriting initialised field in 'atiixp_sht'

Fixes the following W=1 kernel build warning(s):

 drivers/ata/pata_atiixp.c:256:19: warning: initialized field overwritten [-Woverride-init]
 drivers/ata/pata_atiixp.c:256:19: note: (near initialization for ‘atiixp_sht.sg_tablesize’)

Cc: Jens Axboe <axboe@kernel.dk>
Cc: ATI Inc <hyu@ati.com>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210528090502.1799866-7-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>