[SCSI] mvumi: Add Marvell UMI driver

	The Marvell Universal Message Interface (UMI) defines a messaging
interface between host and Marvell products (Plato, for example). It
considers situations of limited system resource and optimized system
performance.
	UMI driver translates host request to message and sends message
to FW via UMI, FW receives message and processes it, then sends response
to UMI driver.
	FW generates an interrupt when it needs to send information or
response to UMI driver

Signed-off-by: Jianyun Li <jyli@marvell.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>