Adds "armvX-none-rvct" targets

Adds "armvX-none-rvct" targets

Adds following targets to configure script to support RVCT compilation
without operating system support (for Profiler or bare metal images).
 - armv5te-none-rvct
 - armv6-none-rvct
 - armv7-none-rvct

To strip OS specific parts from the code "os_support"-config was added
to script and CONFIG_OS_SUPPORT flag is used in the code to exclude OS
specific parts such as OS specific includes and function calls for
timers and threads etc. This was done to enable RVCT compilation for
profiling purposes or running the image on bare metal target with
Lauterbach.

Removed separate AREA directives for READONLY data in armv6 and neon
assembly files to fix the RVCT compilation. Otherwise
"ldr <reg>, =label" syntax would have been needed to prevent linker
errors. This syntax is not supported by older gnu assemblers.

Change-Id: I14f4c68529e8c27397502fbc3010a54e505ddb43