Define ENOTSUP anywhere it isn't defined

I confused ENOTSUP with ENOTSUPP.  Juan's original patch was correct.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

qemu-common.h

@@ -38,7 +38,7 @@
 #ifndef ENOMEDIUM
 #define ENOMEDIUM ENODEV
 #endif
-#if !defined(ENOTSUP) && defined(__OpenBSD__)
+#if !defined(ENOTSUP)
 #define ENOTSUP 4096
 #endif