OPAL_PCI_SET_MVE_ENABLE
-----------------------

#define OPAL_PCI_SET_MVE_ENABLE			34

static int64_t opal_pci_set_mve_enable(uint64_t phb_id, uint32_t mve_number,
				       uint32_t state)

enum OpalMveEnableAction {
	OPAL_DISABLE_MVE = 0,
	OPAL_ENABLE_MVE = 1
};

WARNING: following documentation is from old sources, and is possibly
not representative of OPALv3 as implemented by skiboot. This should be
used as a starting point for full documentation.

The host calls this function to enable or disable an MVE to respond to an MSI
DMA address and message data value.

The phb_id parameter is the value from the PHB node ibm,opal-phbid
    property.

The mve_number is the index, from 0 to ibm,opal,ibm-num-msi-ports minus1

A '1' value of the state parameter indicates to enable the MVE and a '0'
value indicates to disable the MVE.

This call sets the MVE to an enabled (1) or disabled (0) state.

Return value:
	if (!phb)
		return OPAL_PARAMETER;
	if (!phb->ops->set_mve_enable)
		return OPAL_UNSUPPORTED;
