vdso: aarch64 -- Merge fixes from x86

This brings the changes made in the following commits to the
aarch64 copy of the code.

commit 7794f67f
Author: Cyrill Gorcunov <gorcunov@openvz.org>
Date:   Tue Aug 5 13:59:18 2014 +0400

    vdso: x86 -- Fix missing ability to remap vDSO if only one zone present

commit 066add0d
Author: Cyrill Gorcunov <gorcunov@openvz.org>
Date:   Tue Aug 5 13:07:00 2014 +0400

    vdso: x86 -- Simplify vdso_proxify
Signed-off-by: Christopher Covington <cov@codeaurora.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/aarch64/vdso-pie.c

@@ -345,7 +345,8 @@ int vdso_proxify(char *who, struct vdso_symtable *sym_rt,
 
 					remap_rt = (delta_rt ^ delta_this) < 0 ? false : true;
 				}
-			}
+			} else
+				remap_rt = true;
 		}
 	}
 
@@ -378,9 +379,7 @@ int vdso_proxify(char *who, struct vdso_symtable *sym_rt,
 				pr_err("Failed to unmap %s\n", who);
 				return -1;
 			}
-		}
 
-		if (vma_vvar) {
 			if (vma_vdso->start < vma_vvar->start) {
 				ret  = vdso_remap(who, vdso_rt_parked_at, vma_vdso->start, vdso_vma_size(sym_rt));
 				vdso_rt_parked_at += vdso_vma_size(sym_rt);