Preps the organization of the driver so that the bottom half, which
interacts with the hardware, can share common code sequences for
attachment, detachment, initialization, teardown, etc with new hardware.

For very common code sections, which become specific to the interface
type, the driver uses an indirect function call. The function is set at
initialization. For less common sections, such as initialization, the
driver looks at the interface type and calls the routines relative to
the interface.
Signed-off-by: NJames Smart <james.smart@emulex.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>