Simplify HOST_LONG_BITS

Simplify the macro, not depending on headers defines, but compiler
predefined __SIZEOF__POINTER__ only.

Available since gcc 4.3 and clang 2.8.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>

include/qemu/osdep.h

@@ -245,13 +245,7 @@ extern "C" {
 #endif
 
 /* HOST_LONG_BITS is the size of a native pointer in bits. */
-#if UINTPTR_MAX == UINT32_MAX
-# define HOST_LONG_BITS 32
-#elif UINTPTR_MAX == UINT64_MAX
-# define HOST_LONG_BITS 64
-#else
-# error Unknown pointer size
-#endif
+#define HOST_LONG_BITS (__SIZEOF_POINTER__ * 8)
 
 /* Mac OSX has a <stdint.h> bug that incorrectly defines SIZE_MAX with
  * the wrong type. Our replacement isn't usable in preprocessor