[SCSI] ps3rom: sector size should be 512 bytes

It should be desired that 64 KiB is available for ATAPI transferrring.
(Historically) in SCSI/block layer sector size is defined as 512 during
sector-byte calculation.
Originally in ps3rom.c CD_FRAMESIZE (2048) was used, which limited
/sys/block/sr0/queue/max_sectors_kb to 16 KiB (32 sectors).

Signed-off-by: Aegis Lin <aegislin@gmail.com>
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>