imx: mx7ulp: Add soc level initialization codes and functions

Implement soc level functions to get cpu rev, reset cause, enable cache,
etc. We will disable the wdog and init clocks in s_init at very early u-boot
phase.

Since the we are seeking the way to get chip id for mx7ulp, the get_cpu_rev
is hard coded to a fixed value. This may change in future.

Reuse some code in imx-common.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/imx-common/Makefile b/arch/arm/imx-common/Makefile
index da53f62..b7cb434 100644
--- a/arch/arm/imx-common/Makefile
+++ b/arch/arm/imx-common/Makefile
@@ -31,6 +31,10 @@
 obj-$(CONFIG_IMX_BOOTAUX) += imx_bootaux.o
 obj-$(CONFIG_SECURE_BOOT)    += hab.o
 endif
+ifeq ($(SOC),$(filter $(SOC),mx7ulp))
+obj-y  += cache.o
+obj-$(CONFIG_SECURE_BOOT) += hab.o
+endif
 ifeq ($(SOC),$(filter $(SOC),vf610))
 obj-y += ddrmc-vf610.o
 endif