SCSI: megaraid: missing bounds check in mimd_to_kioc()

SCSI: megaraid: missing bounds check in mimd_to_kioc()

commit 3de2260140417759c669d391613d583baf03b0cf upstream.

pthru32->dataxferlen comes from the user so we need to check that it's
not too large so we don't overflow the buffer.

Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Sumit Saxena <sumit.saxena@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>