Staging: dream: Synaptics touchscreen for HTC Dream: check that smbus is available

Check that SMBUS APIs are available in touchscreen driver.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Cc: Trilok Soni <soni.trilok@gmail.com>
Cc: <arve@android.com>
Cc: Brian Swetland <swetland@google.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>