CRIS: Restore mistakenly cleared kernel Makefile

Commit 0fbc0b67 ("cris: remove arch specific early DT functions")
was a bit overzealous in removing the CRIS DT handling,
and the complete contents of the Makefile was erased
instead of just the line for the devicetree file.

This lead to a complete link failure for all SoCs in
the CRIS port due to missing symbols.

Restore the contents except the line for the devicetree file.
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Fixes: 0fbc0b67

arch/cris/kernel/Makefile

+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the CRIS port.
+#
+
+CPPFLAGS_vmlinux.lds := -DDRAM_VIRTUAL_BASE=0x$(CONFIG_ETRAX_DRAM_VIRTUAL_BASE)
+extra-y := vmlinux.lds
+
+obj-y := process.o traps.o irq.o ptrace.o setup.o time.o sys_cris.o
+obj-y += stacktrace.o
+
+obj-$(CONFIG_MODULES)		+= crisksyms.o
+obj-$(CONFIG_MODULES)		+= module.o
+obj-$(CONFIG_SYSTEM_PROFILER)	+= profile.o
+
+clean:
+