Convert CONFIG_PCA953X to Kconfig

This converts the following to Kconfig:
   CONFIG_PCA953X

Cc: Uri Mashiach <uri.mashiach@compulab.co.il>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e007b38..1e4b50e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -520,6 +520,10 @@
 	  Now, max 24 bits chips and PCA953X compatible chips are
 	  supported
 
+config PCA953X
+	bool "NXP's PCA953X series I2C GPIO (legacy driver)"
+	depends on !DM_PCA953X
+
 config MPC8XXX_GPIO
 	bool "Freescale MPC8XXX GPIO driver"
 	depends on DM_GPIO