SPM: Add shim layer to Ivy partition and enable PIE

Add a shim layer that runs at S-EL1 to the Ivy partition.
Also enable Ivy to be built with PIE.

Signed-off-by: Ruari Phipps <ruari.phipps@arm.com>
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: I821a8ac99d07200aec93ca29d182f8ab6716616c
diff --git a/lib/aarch64/exception_stubs.S b/lib/aarch64/exception_stubs.S
index 1d243de..b186e82 100644
--- a/lib/aarch64/exception_stubs.S
+++ b/lib/aarch64/exception_stubs.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2021, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -12,11 +12,6 @@
  * Simplistic exceptions vector table.
  * All entries spin, which means all types of exceptions are unrecoverable.
  */
-	.macro vector_entry_spin name
-	vector_entry \name
-	b \name
-	end_vector_entry \name
-	.endm
 
 vector_base exception_stubs
 vector_entry_spin sync_exception_sp_el0