Fixed compilation errors found on Cygwin64

- The 'Bits' type used in the opl files is incompatible with Bit64s. Modified
  typedef to fix this issue.
- On Windows use Sleep() directly, since msleep() doesn't exist in Cygwin.

bochs/bochs.h

@@ -611,7 +611,7 @@ BX_CPP_INLINE Bit64u bx_bswap64(Bit64u val64)
 #define BX_MUTEX(mutex) CRITICAL_SECTION (mutex)
 #define BX_INIT_MUTEX(mutex)  InitializeCriticalSection(&(mutex))
 #define BX_FINI_MUTEX(mutex) DeleteCriticalSection(&(mutex))
-#define BX_MSLEEP(val) msleep(val)
+#define BX_MSLEEP(val) Sleep(val)
 #else
 #define BX_THREAD_ID(id) pthread_t (id)
 #define BX_THREAD_FUNC(name,arg) void name(void* arg)

bochs/iodev/sound/opl.h

@@ -38,8 +38,8 @@
   define Bits, Bitu, Bit32s, Bit32u, Bit16s, Bit16u, Bit8s, Bit8u here
 */
 #include <stdint.h>
-typedef uintptr_t Bitu;
-typedef intptr_t  Bits;
+typedef Bit64u    Bitu;
+typedef Bit64s    Bits;
 /*
 typedef uint32_t  Bit32u;
 typedef int32_t   Bit32s;