keystone: kconfig: move board select menu and common settings

Becuase the board select menu in arch/arm/Kconfig is too big,
move the Keystone board select menu to keystone/Kconfig.

Move also common settings (CONFIG_SYS_CPU="armv7" and
CONFIG_SYS_SOC="keystone").

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Tom Rini <trini@ti.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
diff --git a/arch/arm/cpu/armv7/keystone/Kconfig b/arch/arm/cpu/armv7/keystone/Kconfig
new file mode 100644
index 0000000..24d0cbe
--- /dev/null
+++ b/arch/arm/cpu/armv7/keystone/Kconfig
@@ -0,0 +1,24 @@
+if ARCH_KEYSTONE
+
+choice
+	prompt "TI Keystone board select"
+
+config TARGET_K2HK_EVM
+	bool "TI Keystone 2 Kepler/Hawking EVM"
+
+config TARGET_K2E_EVM
+	bool "TI Keystone 2 Edison EVM"
+
+endchoice
+
+config SYS_CPU
+	string
+	default "armv7"
+
+config SYS_SOC
+	string
+	default "keystone"
+
+source "board/ti/ks2_evm/Kconfig"
+
+endif