PCI: hv: Fix the definition of vector in hv_compose_msi_msg()

The local variable 'vector' must be u32 rather than u8: see the
struct hv_msi_desc3.

'vector_count' should be u16 rather than u8: see struct hv_msi_desc,
hv_msi_desc2 and hv_msi_desc3.

Fixes: a2bad844

 ("PCI: hv: Fix interrupt mapping for multi-MSI")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Jeffrey Hugo <quic_jhugo@quicinc.com>
Cc: Carl Vanderlip <quic_carlv@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://lore.kernel.org/r/20221027205256.17678-1-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>