If hpet has been initialized before registering hpet driver, the callback
function of hpet_resources will return the status code of -EBUSY, which is
not defined in the ACPI exception table.  So when ACPI checks the status
code of callback function, it will report the unknown exception code.

So the status code in ACPI is used instead of the generic error code in the
ACPI callback function of hpet_resources.
For example: -EBUSY is replaced by AE_ALREADY_EXISTS
	     -EINVAL is replaced by AE_NO_MEMORY

http://bugzilla.kernel.org/show_bug.cgi?id=8630Signed-off-by: NZhao Yakui  <yakui.zhao@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>