dra7xx: Move CONS_INDEX to Kconfig and enable CONFIG_SPL_STACK_ADDR

- Move the CONS_INDEX selection out of CONFIG_SYS_EXTRA_OPTIONS and
  into Kconfig proper.
- While in here, enable CONFIG_SPL_STACK_ADDR

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/ti/dra7xx/Kconfig b/board/ti/dra7xx/Kconfig
index 3bbd866..80341d9 100644
--- a/board/ti/dra7xx/Kconfig
+++ b/board/ti/dra7xx/Kconfig
@@ -9,4 +9,12 @@
 config SYS_CONFIG_NAME
 	default "dra7xx_evm"
 
+config CONS_INDEX
+	int "UART used for console"
+	range 1 6
+	default 1
+	help
+	  The DRA7xx (and AM57x) SoC has a total of 6 UARTs available to it.
+	  Depending on your specific board you may want something other than UART1
+	  here.
 endif