cmd/ti: Update Kconfig logic and Makefile recursion logic

- Add some dependencies to CMD_DDR3 as this is only valid on some
  platforms (which tend to select it as well).
- The proper gate for going in to cmd/ti is not
  CONFIG_TI_COMMON_CMD_OPTIONS as nothing under there is controlled by
  that symbol but the general TI architecture options.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/cmd/ti/Kconfig b/cmd/ti/Kconfig
index db55744..9442c99 100644
--- a/cmd/ti/Kconfig
+++ b/cmd/ti/Kconfig
@@ -2,6 +2,7 @@
 
 config CMD_DDR3
 	bool "command for verifying DDR features"
+	depends on ARCH_KEYSTONE || DRA7XX
 	help
 	   Support for testing ddr3 on TI platforms. This command
 	   supports memory verification, memory comapre and ecc