Further fixes to documentation links

Change-Id: Ib021c721652d96f6c06ea18741f19a72bba1d00f
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
diff --git a/docs/getting_started/rt-svc-writers-guide.rst b/docs/getting_started/rt-svc-writers-guide.rst
index 03212af..6c17a1f 100644
--- a/docs/getting_started/rt-svc-writers-guide.rst
+++ b/docs/getting_started/rt-svc-writers-guide.rst
@@ -300,7 +300,7 @@
 
 .. _SMCCC: http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
 .. _PSCI: http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
-.. _Firmware Design: ../designb_documents/firmware-design.rst
+.. _Firmware Design: ../design/firmware-design.rst
 .. _services: ../../services
 .. _lib/psci: ../../lib/psci
 .. _runtime_svc.h: ../../include/common/runtime_svc.h