Bluetooth: fix build break on hci_sock.c

Linux-next as of 20110217 complains when building for OMAP1.

  LD      vmlinux
`hci_sock_cleanup' referenced in section `.init.text' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o
`hci_sock_cleanup' referenced in section `.init.text' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o
make: *** [vmlinux] Error 1

A recent patch by Gustavo (Bluetooth: Merge L2CAP and SCO modules
into bluetooth.ko) introduced this by calling the hci_sock_cleanup
function in the error path of bt_init.

Fix this by dropping the __exit marking for hci_sock_cleanup.

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>