removed standard header usage in elementwise files, resolved namespace errors

include/ck/tensor_operation/gpu/element/binary_element_wise_operation.hpp

@@ -340,8 +340,8 @@ struct Bilinear
     };
 
     template <>
-    __host__ __device__ constexpr void operator()<std::int8_t, std::int32_t, std::int8_t>(
-        std::int8_t& y, const std::int32_t& x0, const std::int8_t& x1) const
+    __host__ __device__ constexpr void operator()<int8_t, int32_t, int8_t>(
+        int8_t& y, const int32_t& x0, const int8_t& x1) const
     {
         y = type_convert<int8_t>(alpha_ * type_convert<float>(x0) +
                                  beta_ * type_convert<float>(x1));

include/ck/tensor_operation/gpu/element/unary_element_wise_operation.hpp

@@ -714,7 +714,7 @@ struct Cos
                           is_same<T, int32_t>::value,
                       "Data type is not supported by this operation!");
 
-        y = math::cos(x);
+        y = cos(x);
     };
 };