cmd: Add Kconfig option for multiprocessor cmds

Add Kconfig option(CONFIG_CMD_MP) to enable or disable multiprocessor
commands. Compile cmd/mp.c based on CONFIG_CMD_MP.

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/Kconfig b/Kconfig
index c46f4fc..b0e45cd 100644
--- a/Kconfig
+++ b/Kconfig
@@ -454,6 +454,12 @@
 	default 0x10000 if TARGET_TRICORDER
 	default 0x0
 
+config MP
+	bool "Support for multiprocessor"
+	help
+	  This provides an option to bringup different processors
+	  in multiprocessor cases.
+
 config EXAMPLES
 	bool "Compile API examples"
 	depends on !SANDBOX