[MLIR] Add f8E3M4 IEEE 754 type (#101230)

This PR adds `f8E3M4` type to mlir.

`f8E3M4` type  follows IEEE 754 convention

```c
f8E3M4 (IEEE 754)
- Exponent bias: 3
- Maximum stored exponent value: 6 (binary 110)
- Maximum unbiased exponent value: 6 - 3 = 3
- Minimum stored exponent value: 1 (binary 001)
- Minimum unbiased exponent value: 1 − 3 = −2
- Precision specifies the total number of bits used for the significand (mantissa), 
    including implicit leading integer bit = 4 + 1 = 5
- Follows IEEE 754 conventions for representation of special values
- Has Positive and Negative zero
- Has Positive and Negative infinity
- Has NaNs

Additional details:
- Max exp (unbiased): 3
- Min exp (unbiased): -2
- Infinities (+/-): S.111.0000
- Zeros (+/-): S.000.0000
- NaNs: S.111.{0,1}⁴ except S.111.0000
- Max normal number: S.110.1111 = +/-2^(6-3) x (1 + 15/16) = +/-2^3 x 31 x 2^(-4) = +/-15.5
- Min normal number: S.001.0000 = +/-2^(1-3) x (1 + 0) = +/-2^(-2)
- Max subnormal number: S.000.1111 = +/-2^(-2) x 15/16 = +/-2^(-2) x 15 x 2^(-4) = +/-15 x 2^(-6)
- Min subnormal number: S.000.0001 = +/-2^(-2) x 1/16 =  +/-2^(-2) x 2^(-4) = +/-2^(-6)
```

Related PRs:
- [PR-99698](llvm/llvm-project#99698) [APFloat]
Add support for f8E3M4 IEEE 754 type
- [PR-97118](llvm/llvm-project#97118) [MLIR] Add
f8E4M3 IEEE 754 type

Author: apivovarov

IRTypes.cpp

@@ -246,6 +246,26 @@ class PyFloat8E5M2FNUZType
   }
 };
 
+/// Floating Point Type subclass - Float8E3M4Type.
+class PyFloat8E3M4Type : public PyConcreteType<PyFloat8E3M4Type, PyFloatType> {
+public:
+  static constexpr IsAFunctionTy isaFunction = mlirTypeIsAFloat8E3M4;
+  static constexpr GetTypeIDFunctionTy getTypeIdFunction =
+      mlirFloat8E3M4TypeGetTypeID;
+  static constexpr const char *pyClassName = "Float8E3M4Type";
+  using PyConcreteType::PyConcreteType;
+
+  static void bindDerived(ClassTy &c) {
+    c.def_static(
+        "get",
+        [](DefaultingPyMlirContext context) {
+          MlirType t = mlirFloat8E3M4TypeGet(context->get());
+          return PyFloat8E3M4Type(context->getRef(), t);
+        },
+        py::arg("context") = py::none(), "Create a float8_e3m4 type.");
+  }
+};
+
 /// Floating Point Type subclass - BF16Type.
 class PyBF16Type : public PyConcreteType<PyBF16Type, PyFloatType> {
 public:
@@ -864,6 +884,7 @@ void mlir::python::populateIRTypes(py::module &m) {
   PyFloat8E4M3FNUZType::bind(m);
   PyFloat8E4M3B11FNUZType::bind(m);
   PyFloat8E5M2FNUZType::bind(m);
+  PyFloat8E3M4Type::bind(m);
   PyBF16Type::bind(m);
   PyF16Type::bind(m);
   PyTF32Type::bind(m);