Changes in merged posix pager mm0 initialization.

- Moved rootfs from being embedded to mm0 image to being an independent image.
- MM0 boots up to start_init_process with updated boot convention.

conts/posix/mm0/fs/bdev.c

@@ -1,15 +1,19 @@
 /*
  * This is just to allocate some memory as a block device.
  */
+#include <init.h>
 #include <l4/macros.h>
+#include <bootdesc.h>
 #include <memfs/memfs.h>
-
-extern char _start_bdev[];
-extern char _end_bdev[];
-
-__attribute__((section(".data.memfs"))) char blockdevice[MEMFS_TOTAL_SIZE];
+#include <l4lib/arch/syslib.h>
 
 void *vfs_rootdev_open(void)
 {
-	return (void *)_start_bdev;
+	struct svc_image *rootfs_img = bootdesc_get_image_byname("rootfs");
+	unsigned long rootfs_size = rootfs_img->phys_end - rootfs_img->phys_start;
+	
+	BUG_ON(rootfs_size < MEMFS_TOTAL_SIZE);
+
+	/* Map filesystem blocks to virtual memory */
+	return l4_map_helper((void *)rootfs_img->phys_start, __pfn(rootfs_size));
 }