xen/riscv: use printk() instead of early_printk()

As common code is available it is better to use printk() instead
of early_printk().

Also the printing of "Hello from RISC-V world" is dropped as
it is useless and "All set up is enough".

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

xen/arch/riscv/setup.c

@@ -23,9 +23,7 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
 {
     remove_identity_mapping();
 
-    early_printk("Hello from C env\n");
-
-    early_printk("All set up\n");
+    printk("All set up\n");
 
     for ( ;; )
         asm volatile ("wfi");