coredump: Move dump_emit_page() to kill unused warning

If CONFIG_ELF_CORE is not set:

    fs/coredump.c:835:12: error: ‘dump_emit_page’ defined but not used [-Werror=unused-function]
      835 | static int dump_emit_page(struct coredump_params *cprm, struct page *page)
          |            ^~~~~~~~~~~~~~

Fix this by moving dump_emit_page() inside the existing section
protected by #ifdef CONFIG_ELF_CORE.

Fixes: 06bbaa6dc5 ("[coredump] don't use __kernel_write() on kmap_local_page()")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/coredump.c

@@ -838,6 +838,30 @@ static int __dump_skip(struct coredump_params *cprm, size_t nr)
 	}
 }
 
+int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
+{
+	if (cprm->to_skip) {
+		if (!__dump_skip(cprm, cprm->to_skip))
+			return 0;
+		cprm->to_skip = 0;
+	}
+	return __dump_emit(cprm, addr, nr);
+}
+EXPORT_SYMBOL(dump_emit);
+
+void dump_skip_to(struct coredump_params *cprm, unsigned long pos)
+{
+	cprm->to_skip = pos - cprm->pos;
+}
+EXPORT_SYMBOL(dump_skip_to);
+
+void dump_skip(struct coredump_params *cprm, size_t nr)
+{
+	cprm->to_skip += nr;
+}
+EXPORT_SYMBOL(dump_skip);
+
+#ifdef CONFIG_ELF_CORE
 static int dump_emit_page(struct coredump_params *cprm, struct page *page)
 {
 	struct bio_vec bvec = {
@@ -871,30 +895,6 @@ static int dump_emit_page(struct coredump_params *cprm, struct page *page)
 	return 1;
 }
 
-int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
-{
-	if (cprm->to_skip) {
-		if (!__dump_skip(cprm, cprm->to_skip))
-			return 0;
-		cprm->to_skip = 0;
-	}
-	return __dump_emit(cprm, addr, nr);
-}
-EXPORT_SYMBOL(dump_emit);
-
-void dump_skip_to(struct coredump_params *cprm, unsigned long pos)
-{
-	cprm->to_skip = pos - cprm->pos;
-}
-EXPORT_SYMBOL(dump_skip_to);
-
-void dump_skip(struct coredump_params *cprm, size_t nr)
-{
-	cprm->to_skip += nr;
-}
-EXPORT_SYMBOL(dump_skip);
-
-#ifdef CONFIG_ELF_CORE
 int dump_user_range(struct coredump_params *cprm, unsigned long start,
 		    unsigned long len)
 {