[X86] Consistently use __inline__ keyword in intrin.h (llvm#117856)

Using `inline` instead of `__inline__` may cause duplicate symbol errors in some scenarios.

This fixes llvm#117854

Author: momo5502

clang/lib/Headers/intrin.h

@@ -330,33 +330,33 @@ static __inline__ void __DEFAULT_FN_ATTRS __halt(void) {
   __asm__ volatile("hlt");
 }
 
-static inline unsigned char __inbyte(unsigned short port) {
+static __inline__ unsigned char __inbyte(unsigned short port) {
   unsigned char ret;
   __asm__ __volatile__("inb %w1, %b0" : "=a"(ret) : "Nd"(port));
   return ret;
 }
 
-static inline unsigned short __inword(unsigned short port) {
+static __inline__ unsigned short __inword(unsigned short port) {
   unsigned short ret;
   __asm__ __volatile__("inw %w1, %w0" : "=a"(ret) : "Nd"(port));
   return ret;
 }
 
-static inline unsigned long __indword(unsigned short port) {
+static __inline__ unsigned long __indword(unsigned short port) {
   unsigned long ret;
   __asm__ __volatile__("inl %w1, %k0" : "=a"(ret) : "Nd"(port));
   return ret;
 }
 
-static inline void __outbyte(unsigned short port, unsigned char data) {
+static __inline__ void __outbyte(unsigned short port, unsigned char data) {
   __asm__ __volatile__("outb %b0, %w1" : : "a"(data), "Nd"(port));
 }
 
-static inline void __outword(unsigned short port, unsigned short data) {
+static __inline__ void __outword(unsigned short port, unsigned short data) {
   __asm__ __volatile__("outw %w0, %w1" : : "a"(data), "Nd"(port));
 }
 
-static inline void __outdword(unsigned short port, unsigned long data) {
+static __inline__ void __outdword(unsigned short port, unsigned long data) {
   __asm__ __volatile__("outl %k0, %w1" : : "a"(data), "Nd"(port));
 }
 #endif