Build: Compile Mbed TLS as MinSizeRel by default

Changes the build system to compile Mbed TLS without debug symbols by
default. It can still be built with debug symbols by adding
-DMBEDTLS_DEBUG=ON to the CMake command. Most of the time TF-M
developers do not need to debug Mbed TLS, and building it as
"MinSizeRel" by default allows for smaller, faster binaries. It also
eliminates the need for Musca-specific build settings to shrink the
binary size.

Change-Id: I4b691a50f63ddbb4707a196bf7950f8e7603a32c
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
7 files changed