arm: mach-imx: move snvs module

Commit 723f8359c1 ("imx: mx7: snvs: Add an SNVS init routine") noted
that the init_snvs() call likely applies to other i.MX processors, and
this has been found to be true for i.MX8MP.

Move snvs module for future re-use.

Signed-off-by: Ian Ray <ian.ray@gehealthcare.com>

arch/arm/mach-imx/Makefile

@@ -293,3 +293,5 @@ obj-$(CONFIG_ARCH_IMXRT) += imxrt/
 
 obj-$(CONFIG_SPL_BOOTROM_SUPPORT) += spl_imx_romapi.o
 obj-$(CONFIG_IMX8_ROMAPI) += romapi.o
+
+obj-$(CONFIG_MX7) += snvs.o

arch/arm/mach-imx/mx7/Makefile

@@ -3,5 +3,5 @@
 # (C) Copyright 2015 Freescale Semiconductor, Inc.
 #
 
-obj-y	:= soc.o clock.o clock_slice.o ddr.o snvs.o
+obj-y	:= soc.o clock.o clock_slice.o ddr.o
 obj-$(CONFIG_ARMV7_PSCI)  += psci-mx7.o psci-suspend.o

arch/arm/mach-imx/snvs.h

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 Linaro
+ */
+
+void init_snvs(void);