LINUX: Fix Header for major/minor macros, thus removing warnings.

Warnings are as follows:
"In the GNU C Library, "minor" is defined by <sys/sysmacros.h>.
For historical compatibility, it is currently defined by
<sys/types.h> as well, but we plan toremove this soon.
To use "minor", include <sys/sysmacros.h> directly. If you did
not intend to use a system-defined macro "minor", you should
undefine it after including <sys/types.h>"

backends/audiocd/linux/linux-audiocd.cpp

@@ -62,6 +62,7 @@
 #include <linux/cdrom.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
+#include <sys/sysmacros.h>
 #include <sys/types.h>
 
 enum {