tbs2910: fix Kconfig

fix Kconfig for tbs2910 board to prevent crash on relocation

Signed-off-by: Soeren Moch <smoch@web.de>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b9ac59e..be703af 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -650,6 +650,7 @@
 
 config TARGET_TBS2910
 	bool "Support tbs2910"
+	select CPU_V7
 
 config TARGET_TQMA6
 	bool "TQ Systems TQMa6 board"