[X86-64] Support Intel AMX Intrinsic

INTEL ADVANCED MATRIX EXTENSIONS (AMX).
AMX is a new programming paradigm, it has a set of 2-dimensional registers
(TILES) representing sub-arrays from a larger 2-dimensional memory image and
operate on TILES.

These intrinsics use direct TMM register number as its params.

Spec can be found in Chapter 3 here https://software.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D83111
diff --git a/clang/docs/ClangCommandLineReference.rst b/clang/docs/ClangCommandLineReference.rst
index 67c341f..672c4ae 100644
--- a/clang/docs/ClangCommandLineReference.rst
+++ b/clang/docs/ClangCommandLineReference.rst
@@ -3127,6 +3127,12 @@
 
 .. option:: -maes, -mno-aes
 
+.. option:: -mamx-bf16, -mno-amx-bf16
+
+.. option:: -mamx-int8, -mno-amx-int8
+
+.. option:: -mamx-tile, -mno-amx-tile
+
 .. option:: -mavx, -mno-avx
 
 .. option:: -mavx2, -mno-avx2