phase4_enable_disable

[ron minnich]

Here are all the usages we have at present:

agp3dev_enable,
 amd8111_enable,
 amd8111_usb2_enable,
 f71805f_pnp_enable_resources,
 ioapic_enable,
 it8712f_pnp_enable_resources,
 it8716f_pnp_enable_disable,
 rs690_enable,
 sb600_enable,
 setup_onboard,
 w83627hf_pnp_enable_resources,

For each one we need this answer:
1. Is this function needed to enable proper scanning of the device,
i.e. can we discover the device and its functions (if any) without
calling this function.
That determines if we need to call this function in phase3_enable_scan
2. Is this function needed to enable reading resources on this device,
or any child devices? If we don't call this function, can we still get
(e.g.) BAR values?
That determines if we need to call this function in phase4_enable_disable
3. Is this function needed to enable the device?
That determines if we call this function in phase5

So, let's try to work this out. I also want to rename these to some
extent. E.g. w83627hf_pnp_enable_resources: is it enabling *resources*
-- where a resource is an io or memory address range -- or
*devices* -- where a device is a serial or keyboard or whatever.

This confusion is in v2, I'd like not to have it in v3.

ron