shpchp: remove CONFIG_HOTPLUG_PCI_SHPC_POLL_EVENT_MODE

The CONFIG_HOTPLUG_PCI_SHPC_POLL_EVENT_MODE config option is not
needed because polling mechanism for shpc hotplug events can be
enabled through module option 'shpchp_poll_mode'. This patch removes
CONFIG_HOTPLUG_PCI_SHPC_POLL_EVENT_MODE.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>