trusted-services: changes for updated trusted services

* Change compiler from AARCH64_BARE_METAL to ARCH64_LINUX
* Change TS_ENVIRONMENT from "sp" to "config/default-sp"
* Change partition name from "firmware-update" to "fwu"
* Remove mgeneral-regs-only from CFLAGS as it restricts the usage of
neon instructions in MbedTLS
* Link the generated dts from output directory rather than from source
* Include "uuid" in the sp_layout.json which will be used by tf-a while
packaging the FIP
* Install libts.so.2
* Set the install version of pyelftools to 0.31

Signed-off-by: Davidson K <davidson.kumaresan@arm.com>
Signed-off-by: Jackson Cooper-Driver <jackson.cooper-driver@arm.com>