arm: mx6: kconfig: don't select CPU_V7 per board

CPU_V7 is already selected by ARCH_MX6, so no point in selecting it again
by boards that depend on ARCH_MX6.

Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>

arch/arm/cpu/armv7/mx6/Kconfig

@@ -31,7 +31,6 @@ choice
 
 config TARGET_CM_FX6
 	bool "Support CM-FX6"
-	select CPU_V7
 	select SUPPORT_SPL
 	select DM
 	select DM_SERIAL
@@ -39,11 +38,9 @@ config TARGET_CM_FX6
 
 config TARGET_SECOMX6
 	bool "Support secomx6 boards"
-	select CPU_V7
 
 config TARGET_TQMA6
 	bool "TQ Systems TQMa6 board"
-	select CPU_V7
 
 endchoice