use fast_math flag instead of ENV flag for GELU (#1855)

Co-authored-by: kahmed10 <15948690+kahmed10@users.noreply.github.com>

src/targets/gpu/target.cpp

@@ -76,7 +76,6 @@ MIGRAPHX_DECLARE_ENV_VAR(MIGRAPHX_DISABLE_SCHEDULE_PASS)
 MIGRAPHX_DECLARE_ENV_VAR(MIGRAPHX_DISABLE_REDUCE_FUSION)
 MIGRAPHX_DECLARE_ENV_VAR(MIGRAPHX_ENABLE_NHWC)
 MIGRAPHX_DECLARE_ENV_VAR(MIGRAPHX_ENABLE_CK)
-MIGRAPHX_DECLARE_ENV_VAR(MIGRAPHX_DISABLE_FAST_GELU)
 
 struct id_pass
 {
@@ -125,7 +124,7 @@ std::vector<pass> target::get_passes(migraphx::context& gctx, const compile_opti
         inline_module{},
         rewrite_pooling{},
         dead_code_elimination{},
-        enable_pass(not enabled(MIGRAPHX_DISABLE_FAST_GELU{}), rewrite_gelu{}),
+        enable_pass(options.fast_math, rewrite_gelu{}),
         optimize_module{},
         enable_pass(enabled(MIGRAPHX_ENABLE_NHWC{}), layout_nhwc{}),
         dead_code_elimination{},