kconfig: arm: select CPU_V7 for some new boards

This commit adds "select CPU_V7" for some new boards that were not
covered by commit 2e07c249a67e
(kconfig: arm: introduce symbol for ARM CPUs).

Redundant "SYS_CPU" defines and "string" directives should be removed.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Stefan Roese <sr@denx.de>
Acked-by: Georges Savoundararadj <savoundg@gmail.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 79ccc06..da1452f 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -225,9 +225,11 @@
 
 config TARGET_DB_MV784MP_GP
 	bool "Support db-mv784mp-gp"
+	select CPU_V7
 
 config TARGET_MAXBCM
 	bool "Support maxbcm"
+	select CPU_V7
 
 config TARGET_DEVKIT3250
 	bool "Support devkit3250"
@@ -629,6 +631,7 @@
 
 config TARGET_KOSAGI_NOVENA
 	bool "Support Kosagi Novena"
+	select CPU_V7
 
 config TARGET_TQMA6
 	bool "TQ Systems TQMa6 board"