mx6: Select CONFIG_MP with MX6_SMP

It makes sense to select the MP multi processor option at the same time we
select the other SMP options needed for SMP capable i.MX6 SoCs.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>

arch/arm/mach-imx/mx6/Kconfig

@@ -5,6 +5,7 @@ config MX6_SMP
 	select ARM_ERRATA_761320
 	select ARM_ERRATA_794072
 	select ARM_ERRATA_845369
+	select MP
 	bool
 
 config MX6

include/configs/mx6_common.h

@@ -15,7 +15,6 @@
 #define CONFIG_SYS_PL310_BASE	L2_PL310_BASE
 #endif
 
-#define CONFIG_MP
 #endif
 #define CONFIG_BOARD_POSTCLK_INIT
 #define CONFIG_MXC_GPT_HCLK