xen/riscv: build setup code as .init

At the moment, all code and data in setup.c are marked with __init or
__initdata, which is intended to remain this way. Leverage this by using
setup.init.o instead of setup.o in Makefile.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/riscv/Makefile

@@ -12,7 +12,7 @@ obj-y += paging.o
 obj-y += pt.o
 obj-$(CONFIG_RISCV_64) += riscv64/
 obj-y += sbi.o
-obj-y += setup.o
+obj-y += setup.init.o
 obj-y += shutdown.o
 obj-y += smp.o
 obj-y += smpboot.o