efi_loader: fix CopyMem()

CopyMem() must support overlapping buffers. So replace memcpy() by
memmove().

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 88386ff..dbf0d56 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -2483,7 +2483,7 @@
 				size_t length)
 {
 	EFI_ENTRY("%p, %p, %ld", destination, source, (unsigned long)length);
-	memcpy(destination, source, length);
+	memmove(destination, source, length);
 	EFI_EXIT(EFI_SUCCESS);
 }