aesni: support cpuid on WIN32

`__cpuid` has two kinds of signatures in different
headers depending on the target OS. We make it
consistent between the usages ang the included header.

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>

library/aesni.c

@@ -53,7 +53,7 @@ int mbedtls_aesni_has_support(unsigned int what)
     if (!done) {
 #if MBEDTLS_AESNI_HAVE_CODE == 2
         static unsigned info[4] = { 0, 0, 0, 0 };
-#if defined(_MSC_VER)
+#if defined(_WIN32)
         __cpuid(info, 1);
 #else
         __cpuid(1, info[0], info[1], info[2], info[3]);