multiboot: Separate multiboot loading into separate file

Move multiboot loading code into separate files as suggested by Alex Graf.

Signed-off-by: Adam Lackorzynski <adam@os.inf.tu-dresden.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/multiboot.h

@@ -0,0 +1,12 @@
+#ifndef QEMU_MULTIBOOT_H
+#define QEMU_MULTIBOOT_H
+
+int load_multiboot(void *fw_cfg,
+                   FILE *f,
+                   const char *kernel_filename,
+                   const char *initrd_filename,
+                   const char *kernel_cmdline,
+                   int kernel_file_size,
+                   uint8_t *header);
+
+#endif