Remove Markdown documentation

Removed Markdown documents as they have been converted to
reStructuredText.

Change-Id: I3148222eb31258f158f64de4ddcdda4b232ce483
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>

docs/spd/optee-dispatcher.md

-OP-TEE Dispatcher
-=================
-
-[OP-TEE OS] is a Trusted OS running as Secure EL1.
-
-To build and execute OP-TEE follow the instructions at
-[OP-TEE build.git][OP-TEE OS]
-
-- - - - - - - - - - - - - - - - - - - - - - - - - -
-
-_Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved._
-
-[OP-TEE OS]:  https://github.com/OP-TEE/build

docs/spd/trusty-dispatcher.md

-Trusty Dispatcher
-=================
-Trusty is a a set of software components, supporting a Trusted Execution
-Environment (TEE) on mobile devices, published and maintained by Google.
-
-Detailed information and build instructions can be found on the Android
-Open Source Project (AOSP) webpage for Trusty hosted at
-https://source.android.com/security/trusty
-
-Supported platforms
-===================
-Out of all the platforms supported by the ARM Trusted Firmware, Trusty is
-verified and supported by NVIDIA's Tegra SoCs.
-
-