Bluetooth: Move hci_update_page_scan to hci_request.c

This is a left-over from the patch that created hci_request.c. The
hci_update_page_scan functions should have been moved from hci_core.c
there.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>