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 2e07c249
(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>