drivers/gpio is platform-neutral

Update Kconfig and Makefile in drivers/gpio to discourage inappropriate
addition of platform-specific code.

[akpm@linux-foundation.org: fix tpyo]
Signed-by: David Brownell <dbrownell@users.sourceforge.net>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 51c3cdd..e53dcff 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -1,4 +1,8 @@
-# gpio support: dedicated expander chips, etc
+# generic gpio support: dedicated expander chips, etc
+#
+# NOTE: platform-specific GPIO drivers don't belong in the
+# drivers/gpio directory; put them with other platform setup
+# code, IRQ controllers, board init, etc.
 
 ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG