imx: mx7ulp: Add mx7ulp to Kconfig

i.MX7ULP is a new series SoC which has different architecture
from previous i.MX platforms. Create a new cpu folder for it,
and add it to Kconfig.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by : Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/cpu/armv7/mx7ulp/Kconfig b/arch/arm/cpu/armv7/mx7ulp/Kconfig
new file mode 100644
index 0000000..85efd6d
--- /dev/null
+++ b/arch/arm/cpu/armv7/mx7ulp/Kconfig
@@ -0,0 +1,6 @@
+if ARCH_MX7ULP
+
+config SYS_SOC
+	default "mx7ulp"
+
+endif