[PATCH] ppc64 iSeries: make virtual DVD-RAMs writable again

It appears that another test has been added in the Uniform CDROM layer that
must be passed before a DVD-RAM is considered writeable.  This patch
implements an emulation of the needed packet command for the viocd driver.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>