deprecate obsolete pca9539 driver

Use drivers/gpio/pca9539.c instead.

Signed-off-by: eric miao <eric.miao@marvell.com>
Acked-by: Ben Gardner <bgardner@wabtec.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/i2c/chips/pca9539 b/Documentation/i2c/chips/pca9539
index c4fce6a..1d81c53 100644
--- a/Documentation/i2c/chips/pca9539
+++ b/Documentation/i2c/chips/pca9539
@@ -1,6 +1,9 @@
 Kernel driver pca9539
 =====================
 
+NOTE: this driver is deprecated and will be dropped soon, use
+drivers/gpio/pca9539.c instead.
+
 Supported chips:
   * Philips PCA9539
     Prefix: 'pca9539'