imx: mx7: drop select CPU_V7 for board target

drop select CPU_V7 for board target, since ARCH_MX7 selects CPU_V7.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/cpu/armv7/mx7/Kconfig b/arch/arm/cpu/armv7/mx7/Kconfig
index 892ffae..ea19e5c 100644
--- a/arch/arm/cpu/armv7/mx7/Kconfig
+++ b/arch/arm/cpu/armv7/mx7/Kconfig
@@ -13,7 +13,6 @@
 
 config TARGET_MX7DSABRESD
 	bool "mx7dsabresd"
-	select CPU_V7
 	select DM
 	select DM_THERMAL