This whole function is only relevant on cores with revision >= 5, otherwise there's no need to do anything, it always succeeds.

The function has a parameter that requests if the PHY should be connected or not.

If the phy should be connected:

1. Check if coreflagshigh (http://bcm-specs.sipsolutions.net/core_information_registers) contains 0x01, if not fail

2. Set PHYConnected to true
3. Turn on bit 0x800 in coreflagslow

Otherwise:

1. Check if coreflagshigh contains 0x02, if not fail
2. Set PHYConnected to false
3. Turn off bit 0x800 in coreflagslow