[clang] [X86]Add support for _outp{|w|d} (PR #93774)

[Malay Sanghi via cfe-commits]

================
@@ -348,6 +348,20 @@ static inline unsigned long _inpd(unsigned short port) {
   return ret;
 }
 
+static inline int _outp(unsigned short port, int data) {
----------------
MalaySanghi wrote:

There's 2 differences between _outp and __outbyte.

First, the newer intrinsics don't return a value. 

Second, __outbyte signature is

```
void __outbyte(
   unsigned short Port,
   unsigned char Data
);
```

Note that the second input is unsigned char instead of int. This is likely because _outp is supposed to write a byte.

Other than that, I have verified that renaming to __outbyte works and is functionally equivalent. 
When lowered via microsoft's cl, the asm is identical.

https://github.com/llvm/llvm-project/pull/93774