Input: ads7846 - document that it handles tsc2046 too

The TSC2046 is an updated version of the ADS7846 ... mention that in
the Kconfig helptext and driver source.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 693e3b2..b0110fe 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -39,6 +39,7 @@
 /*
  * This code has been heavily tested on a Nokia 770, and lightly
  * tested on other ads7846 devices (OSK/Mistral, Lubbock).
+ * TSC2046 is just newer ads7846 silicon.
  * Support for ads7843 tested on Atmel at91sam926x-EK.
  * Support for ads7845 has only been stubbed in.
  *