usb: typec: ucsi: ucsi: Staticify and stop export of ucsi_init()

usb: typec: ucsi: ucsi: Staticify and stop export of ucsi_init()

It isn't called from anywhere outside of ucsi.c.

Fixes the following W=1 kernel build warning(s):

 drivers/usb/typec/ucsi/ucsi.c:1005:5: warning: no previous prototype for ‘ucsi_init’ [-Wmissing-prototypes]
 1005 | int ucsi_init(struct ucsi *ucsi)
 | ^~~~~~~~~

Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200706133341.476881-25-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>