spi: Kconfig: Mark SOFT_SPI as DEPRECATED

Mark SOFT_SPI as DEPRECATED, this so the resulting build shows
warning for deprecated configuration enabled and associated code
will remove in v2019.07 release.

Cc: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
[trini: Switch to DEPRECATED]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index c2e9180..ef3672f 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -314,6 +314,7 @@
 
 config SOFT_SPI
 	bool "Soft SPI driver"
+	depends on DM_SPI || (DEPRECATED && !DM_SPI)
 	help
 	 Enable Soft SPI driver. This driver is to use GPIO simulate
 	 the SPI protocol.