imx:mx6 remove duplicated includes

There is no need to include asm/bootm.h twice, so remove one.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index ef02972..b354f70 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -21,7 +21,6 @@
 #include <stdbool.h>
 #include <asm/arch/mxc_hdmi.h>
 #include <asm/arch/crm_regs.h>
-#include <asm/bootm.h>
 #include <dm.h>
 #include <imx_thermal.h>