[openmp] Fix building with MSVC for ARM64

[mstorsjo]

Summary

This fixes a typo from 7a795c42ad7f003cd454bf8dbab714714425664c
(https://reviews.llvm.org/D139139). Apparently some codepaths in
that commit weren't actually ever test compiled, since they
can't have worked due to misbalanced parentheses.

Building with Clang (both mingw mode and clang-cl) didn't use
these codepaths, so building in that mode did work.

[tianshilei1992]

LG

[mstorsjo]

Actually, apparently this was already fixed yesterday, in D143940.

openmp/runtime/src/kmp_os.h

 #define KMP_COMPARE_AND_STORE_RET64(p, cv, sv)                                 \
   _InterlockedCompareExchange64((volatile kmp_int64 *)(p), (kmp_int64)(sv),    \
                                 (kmp_int64)(cv))
 
 
 #define KMP_XCHG_FIXED8(p, v)                                                  \
   _InterlockedExchange8((volatile kmp_int8 *)(p), (kmp_int8)(v));
 #define KMP_XCHG_FIXED16(p, v) _InterlockedExchange16((p), (v));
-#define KMP_XCHG_REAL64(p, v) __kmp_xchg_real64((p), (v)));
+#define KMP_XCHG_REAL64(p, v) __kmp_xchg_real64((p), (v));
 
 inline kmp_real64 __kmp_xchg_real64(volatile kmp_real64 *p, kmp_real64 v) {
   kmp_int64 tmp = _InterlockedExchange64((volatile kmp_int64 *)p, *(kmp_int64
   *)&v); return *(kmp_real64 *)&tmp;
 }
 
 #else // !KMP_ARCH_AARCH64