SPM: Extract common debug code used for SPs

In later patches we will want to use the debug code defined in
cactus_debug.c for the Ivy partition, so create a common sp_debug
file for code re-use.

Signed-off-by: Ruari Phipps <ruari.phipps@arm.com>
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
Change-Id: Ifc9cf0043f3f7549b1668623b44d10cae64ddab0
diff --git a/spm/common/sp_debug.h b/spm/common/sp_debug.h
new file mode 100644
index 0000000..8b0bec7
--- /dev/null
+++ b/spm/common/sp_debug.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+enum stdout_route {
+	PL011_AS_STDOUT = 0,
+	HVC_CALL_AS_STDOUT,
+};
+
+void set_putc_impl(enum stdout_route);