Display a machine-type mismatch warning if a little-endian PPC64

compressed kdump created by makedumpfile(8) is used as an argument
with a non-PPC64 crash utility binary.  Without the patch, the
dumpfile is accepted, and the session subsequently fails with a
message indicating that that the vmlinux and dumpfile do not match.
(anderson@redhat.com)

diskdump.c

@@ -548,7 +548,7 @@ read_dump_header(char *file)
 	else if (STREQ(header->utsname.machine, "ppc") &&
 	    machine_type_mismatch(file, "PPC", NULL, 0))
 		goto err;
-	else if (STREQ(header->utsname.machine, "ppc64") &&
+	else if (STRNEQ(header->utsname.machine, "ppc64") &&
 	    machine_type_mismatch(file, "PPC64", NULL, 0))
 		goto err;
 	else if (STRNEQ(header->utsname.machine, "arm") &&