cc/gcc: do not print 'core' or 'final'

In gcc-'s core and final passes, do not print 'core' or 'final' in
log messages. We already print it in step messages.

Also, as we use the core backend to build the bare-metal final gcc,
it can be disturbing to read 'core' while we're in fact in 'final'.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # Compute AVR32-specific values

 CT_DoArchTupleValues() {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="${CT_ARCH}"

     # gcc ./configure flags

     CT_ARCH_WITH_ARCH=

     CT_ARCH_WITH_ABI=

     CT_ARCH_WITH_CPU=

     CT_ARCH_WITH_TUNE=

     CT_ARCH_WITH_FPU=

     CT_ARCH_WITH_FLOAT=

     CT_TARGET_SYS=none

 }