Support Half/BFloat16 in gelu (#7888)

Partial fix for #7748.

Author: swolchok

kernels/portable/cpu/op_gelu.cpp

@@ -37,7 +37,7 @@ Tensor& gelu_out(
   ET_KERNEL_CHECK(
       ctx, tensors_have_same_dim_order(in, out), InvalidArgument, out);
 
-  ET_SWITCH_FLOAT_TYPES(in.scalar_type(), ctx, "gelu.out", CTYPE, [&]() {
+  ET_SWITCH_FLOATHBF16_TYPES(in.scalar_type(), ctx, "gelu.out", CTYPE, [&]() {
     if (approximate == "tanh") {
       apply_unary_map_fn(
           [](const CTYPE x) {

kernels/test/op_gelu_test.cpp

@@ -70,6 +70,14 @@ TEST_F(OpGeluTest, FloatTensors) {
   test_gelu_execution<ScalarType::Float>();
 }
 
+TEST_F(OpGeluTest, HalfTensors) {
+  test_gelu_execution<ScalarType::Half>();
+}
+
+TEST_F(OpGeluTest, BFloat16Tensors) {
+  test_gelu_execution<ScalarType::BFloat16>();
+}
+
 TEST_F(OpGeluTest, DoubleTensors) {
   if (!SupportedFeatures::get()->op_gelu_dtype_double) {
     GTEST_SKIP();