Convert CONFIG_DEEP_SLEEP to Kconfig

This converts the following to Kconfig:
   CONFIG_DEEP_SLEEP

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/freescale/common/Kconfig b/board/freescale/common/Kconfig
index 300b01e..b41d93b 100644
--- a/board/freescale/common/Kconfig
+++ b/board/freescale/common/Kconfig
@@ -22,6 +22,13 @@
 	    esbc_validate - validate signature using RSA verification
 	    esbc_halt - put the core in spin loop (Secure Boot Only)
 
+config DEEP_SLEEP
+	bool "Enable SoC deep sleep feature"
+	default y if ARCH_T1024 || ARCH_T1040 || ARCH_T1042 || ARCH_LS1021A
+	help
+	  Indicates this SoC supports deep sleep feature. If deep sleep is
+	  supported, core will start to execute uboot when wakes up.
+
 config FSL_USE_PCA9547_MUX
 	bool "Enable PCA9547 I2C Mux on Freescale boards"
 	help