Tizen:*: optflags: set __SOFTFP__ for preproc

Tizen:*: optflags: set __SOFTFP__  for preproc

Without it will fail if optflags are not overridden and raise an error like :

  configure: CFLAGS error: CFLAGS may only be used to specify C compiler flags, not macro definitions. \
  Use CPPFLAGS for: -D__SOFTFP__
  configure: error: Can not continue. \
  Fix errors mentioned immediately above this line.

More details at :
https://gcc.gnu.org/onlinedocs/gcc-4.9.2/gcc/Preprocessor-Options.html#index-Wp-986

Change-Id: Ic02777b0aa92f260837060101422629e3f49ed28
Signed-off-by: Philippe Coval <philippe.coval@open.eurogiciel.org>