cdrom: add more GPCMD_* constants

Add GPCMD_* constants for READ_BUFFER, WRITE_12 and WRITE_BUFFER for
completeness.  These will be used libata.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
1 file changed