Instead of blindly resetting every AHCI port, let's just reset only the
controller by default. The user can still request to reset everything
with a new kernel boot argument called ahci_reset_mode which is set
by default to "controller", so the code will only invoke an HBA reset.
This kernel boot argument can be set to 3 different values:
1. "controller" - reset the HBA and skip resetting AHCI ports
2. "none" - don't reset anything, so we rely on the firmware to
initialize the AHCI HBA and ports for us.
3. "complete" - reset the AHCI HBA and ports.
The full system profiling functionality is useful for profiling the
boot performance of the system. Add a new kernel boot option to start
the system with profiling enabled. This lets you disable and view a
profile once the system is booted.
You can use it by running:
```
$ run.sh qcmd boot_prof
```
Previously all of the CommandLine parsing was spread out around the
Kernel. Instead move it all into the Kernel CommandLine class, and
expose a strongly typed API for querying the state of options.
- If there is no VMWare backdoor, don't allocate memory for it.
- Remove the "unsupported" state, instead just don't instantiate.
- Move the command-line parsing from init to the driver.
- Move mouse packet reception from PS2MouseDevice to VMWareBackdoor.
