This patch fixes the .probe failure of twl4030_usb driver if
it is compiled into kernel.

Since twl4030_usb USB transceiver .probe depends on
twl4030-regulator, marking twl4030_usb_init as subsys_initcall_sync
can make it called after twl4030-regulator initialization is finished,
then twl4030_usb USB transceiver driver can be probed successfully.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>