dock: fix eject request process (2.6.27-rc1 regression)

commit 2a7feab28d3fc060d320eaba192e49dad1079b7e introduces a bug.
My thinkpad actually will send an eject_request and we should follow the
eject process to finish the eject, otherwise system still thinks the bay
is present.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>