doc: Fixup some SMCCC links

This is a fixup for patch 3ba55a3c5fa260c9218be1adff8f39fc2a568d68
("docs: Update SMCCC doc, other changes for release"), where some
links names got changed but their references didn't.

Change-Id: I980d04dde338f3539a2ec1ae2e807440587b1cf5
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/docs/components/debugfs-design.rst b/docs/components/debugfs-design.rst
index a4f98d0..2096bdb 100644
--- a/docs/components/debugfs-design.rst
+++ b/docs/components/debugfs-design.rst
@@ -78,7 +78,7 @@
 -------------
 
 The communication with the 9p layer in BL31 is made through an SMC conduit
-(`SMC Calling Convention PDD`_), using a specific SiP Function Id. An NS
+(`SMC Calling Convention`_), using a specific SiP Function Id. An NS
 shared buffer is used to pass path string parameters, or e.g. to exchange
 data on a read operation. Refer to `ARM SiP Services`_ for a description
 of the SMC interface.