Initialize SCTLR_EL1 based on MODE_RW bit

Initializes SCTLR_EL1 based on MODE_RW bit in SPSR for the entry
point. The RES1 bits for SCTLR_EL1 differs for Aarch64 and Aarch32
mode.
Add opteed based on tspd

Adds a dispatcher for OP-TEE based on the test secure payload
dispatcher.

Fixes arm-software/tf-issues#239
Merge pull request #211 from jenswi-linaro/optee_140916

Dispatcher for OPTEE from Linaro SWG