toolchain: clang: compiler opt: -Ofast -> -O3 -ffast-math

clang 20 does not like -Ofast.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

Author: nashif

cmake/compiler/clang/compiler_flags.cmake

@@ -6,6 +6,7 @@ include(${ZEPHYR_BASE}/cmake/compiler/gcc/compiler_flags.cmake)
 # No property flag, clang doesn't understand fortify at all
 set_compiler_property(PROPERTY security_fortify_compile_time)
 set_compiler_property(PROPERTY security_fortify_run_time)
+set_compiler_property(PROPERTY optimization_fast -O3 -ffast-math)
 
 # No printf-return-value optimizations in clang
 set_compiler_property(PROPERTY no_printf_return_value)