[SCSI] megaraid_old: fix READ_CAPACITY

The bulk transfer mode got eleminated by
3f6270ef

.  Unfortunately, this mode is
required for READ_CAPACITY commands on certain cards, so put it back
again.  This fixes a boot failure regression reported by Burton
Windle.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>